In some respects, however, the situation now is even more complicated than in 2002, because terror groups are holding three soldiers captive: Gilad Shalit in the Gaza Strip, and two other soldiers who were captured Wednesday morning on the northern border.

The attack on Israel's northern border was an impressive military achievement for Hezbollah and a ringing failure for the IDF. Despite Israel's intelligence analyses and despite wide operational deployment, Hezbollah has succeeded in carrying out what it has been threatening to do for more than two years - and it couldn't have happened at a more sensitive time.

Israel has until now responded with restraint by bombarding bridges in central Lebanon and attacking Hezbollah positions along the border. But considering the nature of the military high command's current evaluation of the situation, it is clear that the IDF is interested in inflicting a much sharper blow on Lebanon.

Senior officers in the IDF say that the Lebanese government is responsible for the soldiers' abduction. According to the officers, if the kidnapped soldiers are not returned alive and well, the Lebanese civilian infrastructures will regress 20, or even 50 years.

Lebanon has invested considerable resources in the rehabilitation of its civilian infrastructures from the damage sustained during its civil war in the 1970s and the years of war with Israel throughout the 1980s and 1990s.

If Israel is having difficulty in deterring Hamas in Gaza, and certainly if it is unable to bring the crisis to a conclusion, indeed Hezbollah is a much more sophisticated and experienced rival than its Palestinian counterpart.

It is safe to assume that Hezbollah planned the abduction months in advance, and that the Shi'ite organization has made every effort to conceal the location where the kidnapped soldiers are being held.

From another perspective, however, the opening of a new front somewhat eases Israel's dilemma. It now seems that the government may be able to stop acting like it is walking on eggshells, as it has thus far.

There is every indication that Israel is on its way to a wide escalation of its military operations, both in the north and in the Gaza Strip.

Lebanese police said 27 civilians, including 10 children, were killed in a wave of attacks Thursday, including a strike on Hezbollah TV, after what Israeli Prime Minister Ehud Olmert branded an "act of war".

The killing of eight soldiers and the capture of another two by Hezbollah militants in fighting on the volatile Israel-Lebanon border Wednesday opened up a dangerous new front in the Middle East conflict.

Israeli warplanes also bombed the Palestinian foreign ministry in the Gaza Strip overnight in the latest offensive over the seizure of an Israeli soldier by Palestinian militants three weeks ago.

A total of 70 Palestinians have been killed in the military onslaught against Gaza, which the United Nations has warned is causing a humanitarian crisis in one of the most densely populated areas on earth.

World leaders have issued urgent appeals for restraint, although Israel's top ally, the United States, held
Syria and Iran responsible for the fighting on the Lebanese-Israeli border, the deadliest since Israel ended its 22-year occupation of south Lebanon in May 2000.

The Israeli army said it attacked the airport because it "is used as a central hub for the transfer of weapons and supplies to the Hezbollah terror organization."

Hezbollah, or the Party of God, whose militia was instrumental in forcing Israeli troops out of Lebanon, said it was demanding the release of Arab prisoners in return for the soldiers.

"They will only return home through indirect negotiations and an exchange of prisoners," Hezbollah chief Hassan Nasrallah said.

But Olmert, facing the most serious test of his leadership since being sworn in as premier in May, insisted there would be no negotiations.

"This was an act of war without any provocation on the sovereign territory... of the state of Israel," he said.

On Wednesday, Israeli fighter jets, gunboats and artillery had pounded Lebanon, hitting Hezbollah targets and about 10 bridges, cutting off the highway linking Beirut to the south.

Lebanon said a total of 31 people had been killed in the past 24 hours, including an off-duty soldier, while Hezbollah said one of its militants was also killed.

The Israeli cabinet, meeting in emergency session late Wednesday, gave the green light to "harsh and aggressive" action against Lebanon, which has been mired in its own political crisis since the murder of ex-premier Rafiq Hariri in 2005 and is still rebuilding after the devastating 1975-1990 civil war.

Israel has already called up a rapid-reaction force of 6,000 troops.

"The Lebanese government, which allowed Hezbollah to commit an act of war against Israel, will pay a heavy price. The rules of the game have changed," Justice Minister Haim Ramon said.

The Lebanese government -- which includes a Hezbollah minister -- denied any involvement in the Hezbollah action and demanded an urgent UN Security Council meeting.

Prime Minister Fuad Siniora also called up a host of world leaders "to ask them to help Lebanon in the face of the aggression and in order to contain the situation."

Yemen also called for an emergency meeting of the 22-member Arab League.

The White House, which considers Hezbollah a terrorist outfit, condemned the capture of the soldiers and pointed the finger at Israel's two main foes, Iran and Syria, which both bankroll the fundamentalist Shiite movement.

Washington also defended Israel's ground incursion into Lebanon, saying its chief Middle East ally was entitled to defend itself against "terrorist" attacks.

UN chief Kofi Annan urged all sides to show restraint and to protect civilians.

News of the captured soldiers was greeted with celebratory gunfire across the southern suburbs of Beirut -- a Hezbollah stronghold -- while some residents handed out candy to passing motorists .

"Long live Hezbollah, death to Israel," chanted youths.

The governing Palestinian Islamist movement Hamas, whose military wing is one of three groups holding another soldier captive in Gaza, said the latest abductions showed the "weakness of the Israeli army."

Israel has been on high alert for possible retaliation following its threats to kill Hamas leaders in Damascus and since it sent warplanes over a Syrian presidential palace in a show of force last month.

The return of Israeli troops to Gaza 10 months after the army ended a 38-year-occupation has already evoked painful memories of its disastrous full-scale invasion of Lebanon in 1982 where soldiers became bogged down in a deadly quagmire before finally leaving.

The flare-up on the northern border came as Israel pressed on with its offensive in Gaza, striking the Palestinian foreign ministry overnight and killing 23 people, including nine members of the same family in an air strike on the home of a Hamas leader.

Israel has launched wave after wave of air strikes in Gaza in a bid to stop militant rocket attacks and secure the release of an Israeli corporal capture on June 25 by three groups including the armed wing of Hamas -- which is branded a terrorist movement by Israel and the West.

The groups have demanded the release of 1,000 Palestinian, Arab, Muslim and other prisoners but Israel has refused.

The latest abductions and killings of Israeli soldiers are likely to raise embarrassing questions about the Jewish state's military, which considers itself one of the strongest in the world.

In January 2004, Israel and Hezbollah carried out a swap through German mediation that saw hundreds of Arab detainees released, the return of the bodies of three soldiers, and the freeing of an Israeli businessman.

Speaking in Germany, he said Israel had the right to defend itself, but its action should not weaken the Lebanese government.

France and Russia condemned Israel's "disproportionate use of force".

Blockade

An Israeli military spokesman said Israeli naval ships had entered Lebanese waters to block the transfer of "terrorists and weapons to the terror organisations operating in Lebanon".

Earlier, three missiles hit runways at Beirut airport, the country's only international airport, forcing its closure. Flights have been diverted to Cyprus.

An Israeli army spokesman said the airport was used to supply weapons to Hezbollah.

The blockade follows wide-ranging Israeli air raids on southern Lebanon, which killed at least 35 civilians.

Among the dead were two whole families - one of 10 people and one of seven - killed in the homes near the town of Nabatiyeh, officials said.

The Hezbollah television station al-Manar in southern Beirut was also hit, injuring three.

Responsibility

Israel said its jets hit 40 Hezbollah targets.

Israel has said it holds Lebanon responsible for the soldiers' capture and views it as an "act of war".

Hezbollah has said the captured soldiers will not be returned without a release deal for Palestinian, Lebanese and other Arab prisoners held in Israeli jails.

Lebanese Prime Minister Fuad Siniora denied any knowledge of the Hezbollah operation and refused to take responsibility for the soldiers' capture.

Hezbollah's political wing is a significant force in Lebanese politics and has one government minister, while its powerful military wing has controlled the border zone since Israeli forces pulled out in 2000.

Volatile mix

Israeli Defence Minister Amir Peretz said Israel would "not allow Hezbollah forces to remain on the borders of the state of Israel".

In Gaza, Israeli jets attacked the Palestinian foreign ministry building in Gaza City, injuring at least 10 people.

Israel has kept up air strikes and other military action against Gaza since the capture of Israeli soldier Cpl Gilad Shalit by Palestinian militants two weeks ago.

The BBC's World Affair's correspondent Nick Childs says the confrontations in Gaza and Lebanon are ringing alarm bells among world leaders.

He says the combination of an untried and apparently uncertain Israeli government, plus tensions that could easily extend to Syria and Iran, are creating a volatile mixture.

There were no immediate reports of casualties. However, the attack raised the possibility that the Lebanese army could be drawn into the conflict between Israeli forces and Hezbollah guerrillas, who are holding two Israeli soldiers and have fired rockets into northern Israel.

Earlier, the Israeli air force attacked Rafik Hariri International Airport. Warplanes struck three runways, leaving a large crater and seven smaller holes, airport officials said.

The Israeli military said the airport strike and the blockade were intended to cut off supplies to Hezbollah, and that the Lebanese government must move to clamp down on the Beirut-based militants.

"We are taking the Lebanese government as the one who is carrying all the responsibility on its shoulders regarding this area and regarding the future of Lebanon," said Brig.-Gen. Dan Halutz.

The Israeli air force may attack Beirut or any other place in Lebanon, he added.

"Nothing is safe [in Lebanon], as simple as that," Halutz said.

The offensive follows the capture of the two Israeli soldiers in a cross-border raid by Hezbollah militants. Eight Israeli soldiers were killed in border clashes.

Hezbollah leaders offered to exchange the captured soldiers for Arab prisoners currently held in Israeli jails.

Israeli Prime Minister Ehud Olmert called the Hezbollah raid an "act of war."

After sending ground troops across the Lebanese border Wednesday for the first time in six years, Israel launched air strikes overnight, targeting roads and bridges.

Hezbollah responded by firing rockets into northern Israel, killing a woman who was on her balcony and injuring five more, according to officials.

Police said 52 Lebanese civilians, including 15 children, were killed in attacks on Hezbollah targets in Beirut's southern suburbs and across southern Lebanon.

Security sources said the air strikes in south Lebanon also wounded 100 people. Ten members of a family were killed in Dweir village and seven family members died in Baflay.

Israeli warplanes later blasted runways at the main army air base in eastern Lebanon near Syria's border.

Lebanese police said that Israeli jets had dropped two bombs on the runway at the Rayak air base in the eastern Bekaa Valley, damaging it.

There were no reports of casualties.

Lebanon said on Thursday its only international airport will remain shut for at least 48 hours.

Mohammed Safadi, the transport minister, told reporters that "The airport will be partly operational within 48 hours, but reopening the airport is a political decision that will be decided by the cabinet,"

"The runways have all been hit, although some less than others," he said.

Retaliation

The air strikes triggered Hizbollah fighters to retaliate by firing rockets at northern Israel.

Israel media said at least 70 rockets had slammed into towns and villages in northern Israel.

Worst affected was the coastal city of Nahariya, nearly 10km south of the Lebanese border.

The Magen David Adom ambulance service said a 40-year-old woman was killed when a Katyusha rocket hit her apartment in Nahariya. Medics said 27 people, including children, had been wounded in the city.

They said seven rockets hit Safed, wounding many.

Safed is some 15km inside the Israeli border with Lebanon and among the furthest struck.

Hizbollah said it had fired 60 rockets at Nahariya.

Hizbollah also said on Thursday that it would bombard Israel's third-largest city of Haifa if it targets Beirut. Haifa is 35km south of the Lebanon border.

Russian Foreign Ministry Spokesman Mikhail Kamynin denounced both Israel's attack on Lebanon and its on-going operations against the Palestinian territories. "The continuing destruction by Israel of civilian infrastructure in Lebanon and in Palestinian territory (and) the disproportionate use of force from which civilian populations suffer cannot be understood and justified," he said.

"The attack on Beirut international airport is a dangerous step on the way to military escalation," he added, calling on all sides to stop a slip towards war.

Israel struck Beirut airport and began enforcing a naval blockade of Lebanon on Thursday, intensifying reprisals after Hezbollah seized two Israeli soldiers and killed eight in cross-border attacks a day earlier.

Douste-Blazy said: "For several hours, there has been a bombardment of an airport of an entirely sovereign country, a friend of France ... this is a disproportionate act of war." Douste-Blazy also condemned Hizbollah's firing of rockets into northern Israel and the kidnapping of the soldiers, telling Europe 1 radio these were "irresponsible acts."

"The only solution is a return to reason by both sides," he said. "We are calling for a lowering of tensions," he said.

The Israeli attacks have killed 36 Lebanese civilians. Hezbollah fired barrages of rockets into towns across northern Israel on Thursday, killing one civilian and wounding 29 others in their heaviest bombardment in a decade.

The violence was the worst between Israel and Lebanon since 1996 when Israeli troops still occupied part of the south. It coincided with a major Israeli offensive into the Gaza Strip to retrieve a captured soldier and halt Palestinian rocket fire.

The United States held back from criticizing Israel but called for a lowering of tensions. "We are urging restraint on both sides, recognizing Israel's right to defend itself," a U.S. administration official said, speaking on condition of anonymity.

The U.S. official reiterated the White House's blame of Syria and Iran for the Hezbollah attacks on Israeli soldiers.

"The Syrians and the Iranians bear some responsibility by virtue of their harboring Hezbollah," the official said.

President George W. Bush, who is traveling in Germany for meetings with Chancellor Angela Merkel, was expected to discuss the Lebanon situation at a news conference later on Thursday.

Spain demanded a release of the kidnapped soldiers and "an end to armed aggression against Israel."

"We also ask Israel to act with moderation, in proportion to what has happened, keeping in mind how important it is not to allow the violence to spread, which would endanger the stability of the region with civilians, once again, the main victim," the Spanish foreign ministry said in a statement.

The EU Commissioner for external relations Benita Ferrero- Waldner is "very alarmed" at the escalation of violence between Israel and Lebanon, her spokesperson Emma Udwin told the daily news conference at the Commission in Brussels.

"We condemn unreservedly the kidnapping and in particular the kidnapping of the two Israeli soldiers yesterday by Hizbollah. The soldiers must be released and returned safely immediately," Udwin said.

Commissioner Ferrero-Waldner, who visited Lebanon only last week, "is shocked at the scale of violence that this incident has unleashed on both sides, that is the loss of life of a large number of innocent people, including many children as well as extensive damage to Lebanese infrastructure," said the spokesperson.

"All parties must respect their obligations under international law to protect civilians from the effects of the conflict," said Udwin adding that it is necessary that the Lebanese government extend it control all over Lebanese territory.

She evaded replying to repeated questions by reporters as to why the EU is condemning the kidnapping of two Israeli soldiers and not condemning the killing of over 46 Lebanese civilians, including many children, and the violation of international law by Israeli attacks on civilian targets in Lebanon.

Moreover, the EU has not condemned the kidnapping of Palestinian ministers and legislators in Gaza by the Zionist army.

"Israel has the right to defend herself," Bush told a news conference after talks with German Chancellor Angela Merkel. "Secondly, whatever Israel does should not weaken the ... government in Lebanon."

Bush and Merkel made clear at a joint news conference they felt Israel's actions in seeking kidnapped soldiers and responding to Hizbollah rocket attacks were justified.

But Russian Foreign Minister Sergei Lavrov denounced both Israel's attack on Lebanon and its operations against the Palestinian territories.

"This is a disproportionate response to what has happened and if both sides are going to drive each other into a tight corner then I think that all this will develop in a very dramatic and tragic way," he told reporters on a flight from Paris to Moscow, Interfax news agency reported.

Israel struck Beirut airport and began enforcing a naval blockade of Lebanon on Thursday, intensifying reprisals after Hizbollah seized two Israeli soldiers and killed eight in cross-border attacks on Wednesday.

The Israeli attacks have killed 52 Lebanese civilians.

"DISPROPORTIONATE"

French Foreign Minister Philippe Douste-Blazy called Israel's bombardment of Beirut airport "a disproportionate act of war," saying there was a real risk of a regional war.

Douste-Blazy also condemned Hizbollah's firing of rockets into northern Israel and the seizure of the soldiers, telling Europe 1 radio these were "irresponsible acts."

"The only solution is a return to reason by both sides," he said. "We are calling for a lowering of tensions."

Hizbollah fired barrages of rockets into towns across northern Israel on Thursday, killing one civilian and wounding 29 others in their heaviest bombardment in a decade.

The violence is the worst between Israel and Lebanon since 1996 when Israeli troops still occupied part of the south.

Bush said there was concern that any activities by Israel to protect herself would weaken the Lebanese government.

"Having said all that, people need to protect themselves. There are terrorists who will blow up innocent people in order to achieve tactical objectives. In this case, the objective is to stop the advance of peace," he added.

British Prime Minister Tony Blair called on all sides in the Middle East crisis to exercise restraint, act proportionately and get back to the negotiating table as soon as possible.

"Overall, let us remember how these problems have arisen which is first and foremost the kidnappings. We condemn these kidnappings and call for the soldiers involved to be released," Blair's official spokesman said.

Secretary of State Condoleezza Rice expressed determination to achieve the release of the kidnapped soldiers and urged all sides to "act with restraint to resolve this incident peacefully."

"Syria has a special responsibility to use its influence to support a positive outcome," she said in a statement.

Southern Lebanon became the second front in the fight against Islamic militants by Israel, which already is waging an operation to free a soldier captured by the Palestinian militant group Hamas in the Gaza Strip.

"This is a terrorist attack and it is clearly timed to exacerbate already high tensions in the region and sow further violence," Jones said.

He said Rice, on a diplomatic trip to Paris, had been in direct contact with the parties in the region "with the purpose of holding Hezbollah accountable for its action."

"We also hold Syria and Iran - which directly support Hezbollah - responsible for this attack and for the ensuing violence," Jones said. "Hezbollah's terrorism is not in Lebanon's interest.

"This attack demonstrates that Hezbollah's continued impunity to arm itself and carry out operations from Lebanese territory is a direct threat to the security of the Lebanese people and the sovereignty of the Lebanese government," Jones said.

Syria's vice president, Farouk al-Sharaa, blamed Israel for the violence both in Lebanon and the Palestinian territories and denied that his country had a role in the abductions of the soldiers.

"For sure, the occupation (of the Palestinian territories) is the cause provoking both Lebanese and Palestinian people, and that's why there is Lebanese and Palestinian resistance," he said.

Some of Hamas' top leaders live in Syria, putting Damascus at the center of blame by Israel and the United States.