President George W Bush is said to be so alarmed by the threat of Iran's hard-line leader, Mahmoud Ahmedinejad, that privately he refers to him as "the new Hitler", says Seymour Hersh, who broke the story of the Abu Ghraib Iraqi prisoner abuse scandal.

Some US military chiefs have unsuccessfully urged the White House to drop the nuclear option from its war plans, Hersh writes in The New Yorker magazine. The conviction that Mr Ahmedinejad would attack Israel or US forces in the Middle East, if Iran obtains atomic weapons, is what drives American planning for the destruction of Teheran's nuclear programme.

Hersh claims that one of the plans, presented to the White House by the Pentagon, entails the use of a bunker-buster tactical nuclear weapon, such as the B61-11, against underground nuclear sites. One alleged target is Iran's main centrifuge plant, at Natanz, 200 miles south of Teheran.

Although Iran claims that its nuclear programme is peaceful, US and European intelligence agencies are certain that Teheran is trying to develop atomic weapons. In contrast to the run-up to the Iraq invasion, there are no disagreements within Western intelligence about Iran's plans.

This newspaper disclosed recently that senior Pentagon strategists are updating plans to strike Iran's nuclear sites with long-distance B2 bombers and submarine-launched missiles. And last week, the Sunday Telegraph reported a secret meeting at the Ministry of Defence where military chiefs and officials from Downing Street and the Foreign Office discussed the consequences of an American-led attack on Iran, and Britain's role in any such action.

The military option is opposed by London and other European capitals. But there are growing fears in No 10 and the Foreign Office that the British-led push for a diplomatic solution to the Iranian nuclear stand-off, will be swept aside by hawks in Washington. Hersh says that within the Bush administration, there are concerns that even a pummelling by conventional strikes, may not sufficiently damage Iran's buried nuclear plants.

Iran has been developing a series of bunkers and facilities to provide hidden command centres for its leaders and to protect its nuclear infrastructure. The lack of reliable intelligence about these subterranean facilities, is fuelling pressure for tactical nuclear weapons to be included in the strike plans as the only guaranteed means to destroy all the sites simultaneously.

The attention given to the nuclear option has created serious misgivings among the joint chiefs of staff, and some officers have talked about resigning, Hersh has been told. The military chiefs sought to remove the nuclear option from the evolving war plans for Iran, without success, a former senior intelligence officer said.

The Pentagon consultant on the war on terror confirmed that some in the administration were looking seriously at this option, which he linked to a resurgence of interest in tactical nuclear weapons among defence department political appointees.

The election of Mr Ahmedinejad last year, has hardened attitudes within the Bush Administration. The Iranian president has said that Israel should be "wiped off the map". He has drafted in former fellow Revolutionary Guards commanders to run the nuclear programme, in further signs that he is preparing to back his threats with action.

Mr Bush and others in the White House view him as a potential Adolf Hitler, a former senior intelligence official told Hersh. "That's the name they're using. They say, 'Will Iran get a strategic weapon and threaten another world war?' "

Despite America's public commitment to diplomacy, there is a growing belief in Washington that the only solution to the crisis is regime change. A senior Pentagon consultant said that Mr Bush believes that he must do "what no Democrat or Republican, if elected in the future, would have the courage to do," and "that saving Iran is going to be his legacy".

Publicly, the US insists it remains committed to diplomacy to solve the crisis. But with Russia apparently intent on vetoing any threat of punitive action at the UN, the Bush administration is also planning for unilateral military action. Hersh repeated his claims that the US has intensified clandestine activities inside Iran, using special forces to identify targets and establish contact with anti-Teheran ethnic-minority groups.

The senior defence officials said that Mr Bush is "determined to deny Iran the opportunity to begin a pilot programme, planned for this spring, to enrich uranium".

"The Iranians will retaliate, and they have many possibilities in an area where there are many vulnerabilities, from our troop positions to the oil and gas in the region that can be interrupted, to attacks on
Israel, to the conduct of terrorism," he said.

Zinni made his remarks after the publication of a pair of reports this weekend saying that the administration is seriously considering military action against Iran, amid a stalemate in diplomatic efforts.

The New Yorker magazine reported in its April 17 issue that the administration is planning a massive bombing campaign against Iran, including use of bunker-buster nuclear bombs to destroy a key suspected Iranian nuclear weapons facility.

The article by investigative journalist Seymour Hersh said that Bush and others in the White House have come to view Iranian President Mahmoud Ahmadinejad as a potential "Adolf Hitler."

"That's the name they're using," Hersh quoted a former senior intelligence official as saying.

Hersh told CNN's Late Edition show that a "messianic" president feels driven to try to contain Iran and that the White House is determined to keep open a nuclear option against strong objections from some top
Pentagon officials.

"It's the fact that the White House wouldn't let it go that has got the JCS (Joint Chiefs of Staff) in an uproar," he said.

"He (Bush) thinks, as I wrote, that he's the only one now who will have the courage to do it," said Hersh, the reporter who also broke the Abu Ghraib prison abuse scandal.

Hersh reports in his article that the administration already has advance forces on the ground in Iran.

"I think it's fraught with danger. But they're there," he told CNN.

Democratic Senator John Kerry, one of the administration's most outspoken critics, assailed the White House for what he said is its too-ready reliance on military might.

"That is another example of the shoot-from-the-hip, cowboy diplomacy of this administration," the former Democratic presidential contender said.

"For us to think about exploding tactical nuclear weapons in some way is the height of irresponsibility. It would be destructive to any non-proliferation efforts and the military assessment is, it would not work," he told NBC television's "Meet the Press" program.

Meanwhile, according to a report Sunday in the Washington Post, Bush is studying options for military strikes against Iran as part of a broader strategy of coercive diplomacy to pressure Tehran to abandon its alleged nuclear program.

Citing unnamed US officials and independent analysts, the newspaper said no attack appears likely in the short term, but officials are using the threat to convince Iranians of the seriousness of its intentions.

The paper said Bush views Tehran as a serious menace that must be dealt with before his presidency ends. The White House, in its new National Security Strategy, labeled Iran the most serious challenge to the United States posed by any country.

Zinni said he shared Washington's concerns about Tehran's motives, but said diplomatic efforts should first be exhausted.

"I believe that if the international community would stand fast, the Russians and the Chinese would stay with us, I think that kind of pressure, the fear of being isolated and condemned as a rogue state could have the effect that we need to halt the program.

"I'm not saying that there isn't a military action that will become necessary at some point," Zinni continued.

"But I believe ... when you take that military action, you have to ask the question, 'and then what?' Because you're going to have a series of those 'and then whats' down the road," he said.

Hersh told CNN however, that the White House has spurned Tehran's overtures for dialogue.

"This president is not talking to the Iranians. They are trying very hard to make contact, I can assure you of that, in many different forms," he said.

"He's not talking. And there's no public pressure on the White House to start bilateral talks. And that's what amazes everybody," he said.

The United Nations has called on Iran to halt uranium enrichment, which the West believes Iran is pursuing to acquire technology to make a nuclear bomb. Iran has rejected the demand and insists it only wants to make fuel for civilian uses.

Iran's decision in January to resume enrichment prompted Britain, France and Germany to break off 2-1/2 years of EU talks with Tehran and back a U.S. demand to refer Iran to the U.N. Security Council, which can impose sanctions.

Asefi said Iran was ready to continue its cooperation with the International Atomic Energy Agency and said IAEA chief Mohamed ElBaradei would visit Iran by Friday to discuss Iran's cooperation with the IAEA.

"We have always had good cooperation with the IAEA and we will continue to do so," he said.

ElBaradei is expected to provide a report to the Council on Iran's nuclear programme entitled "the process of Iranian compliance" at the end of this month.

ElBaradei has said he has found no proof of a weapons programme in Iran but at the same time has said he cannot give the Islamic Republic a clean bill of health.

An IAEA official has said earlier that ElBaradei would travel to Iran on Tuesday or Wednesday for a day of meetings in Tehran to try to win more cooperation from Tehran.

Iran has branded the reports as a "psychological war launched by Americans because they feel angry and desperate regarding Iran's nuclear dossier".

"We will stand by our right to nuclear technology... Iran is not afraid of threatening language," Foreign Ministry spokesman Hamid Reza Asefi said on Sunday.

Western powers fear Iran is developing a nuclear bomb. Iran says its nuclear programme is for civilian use.

'World war'

The US magazine article, by journalist Seymour Hersh, makes three main claims:

US clandestine activities inside Iran have increased

Planning for a possible air attack has intensified

The option of using of tactical nuclear weapons to ensure the destruction of well-protected Iranian nuclear facilities is still on the table.

Mr Hersh also quoted a former senior intelligence official as saying that President Bush and others in the White House were referring to Iranian President Mahmoud Ahmadinejad as a potential Adolf Hitler threatening another world war.

Speaking to the BBC, Mr Hersh said many US allies felt Iran was two to 10 years away from developing a nuclear bomb and that the real aim was regime change.

"No matter what Iran would do, I think in the short run some people are afraid the president will want to go - just as he wanted to go on Iraq," he said.

He said he believed the president felt military action against Iran was something only he could do. "It's messianic, I quote somebody as saying," he said.

Planning for military action had moved beyond the contingency stage and into direct operational planning, he added.

Referring to Mr Straw's comments, he said there were questions about how much information the US government was sharing with its European allies.

'Vulnerabilities'

Retired General Anthony Zinni, the former head of US Central Command, said on Sunday any plan to use military force against Iran was risky.

"The Iranians will retaliate, and they have many possibilities in an area where there are many vulnerabilities, from our troop positions to the oil and gas in the region that can be interrupted, to attacks on Israel, to the conduct of terrorism," he told the Associated Press news agency.

Talk of military strikes against Iran have been prompted by Iran's refusal to halt nuclear work.

Last month, the UN Security Council gave Iran 30 days to halt its nuclear research, or run the risk of action such as possible sanctions.

Iranian Foreign Ministry spokesman Hamid-Reza Asefi was quoted by the official IRNA news agency as saying that no date had been fixed for Iran-U.S. talks on Iraqi issues yet.

"Iran has announced that talks with the U.S. have nothing to do with interference in the establishment of a new government in Iraq and this case is related to the Iraqi nation," said the spokesman." Talks with the U.S. in this respect need planning and so far no arrangements have been made," he stressed.

Iraqi Shiite, Kurdish and Sunni leaders are still haggling over the make-up of a new government, almost four months after the December general elections.

Asefi also said that the date would be announced explicitly when all issues concerned became definite.

When asked about the repeated calls from U.S. officials for talks recently, Asefi said Iran had given negative responses to the calls considering U.S. records, but "positively responded despite pessimism and precautions" when Iraqi officials raised this issue.

To hold talks is aimed to discuss withdrawal of the U.S. forces from Iraq and improvement of the U.S. conduct in that country, he said.

Similarly, Iranian President Mahmoud Ahmadinejad said on March 25 that Iran would hold talks with the U.S. for the sake of the Iraqi people although the Islamic Republic did not trust the U.S. administration.

Meanwhile, local daily Kayhan reported that a group of students on Saturday held a protest against the proposed negotiations with the U.S. in front of the Supreme National Security Council, terming the dialogue with Washington as "betrayal of Islam."

On March 16, Secretary of the Iranian Supreme National Security Council Ali Larijani first voiced Iran's readiness to hold talks with the U.S. to solve Iraqi problems as proposed by Iraqi Shiite political leader Abdul Aziz al-Hakim.

In response, the White House authorized the U.S. Ambassador to Iraq Zalmay Khalilzad to hold talks with Iran.

Iran, which has been accused by the United States of allowing weapons and insurgents to cross into Iraq, had previously said it was not interested in discussions before the U.S. troops pulled out of Iraq.

His warnings, made at a lunchtime meeting sponsored by Deutsche Bank in Berlin, were combined with a charm offensive during a two-day visit to Germany. He met Merkel and officials of Germany's biggest companies and banks, which have built on traditionally strong ties to establish a strong presence in Russia.

Germany is still one of Russia's most important Western partners, despite Merkel's attempts to rebalance her foreign policy by breaking the special axis that her Social Democratic predecessor, Gerhard Schröder, had forged with Paris and Moscow at the expense of ties with the United States and the EU.

Russia's image has deteriorated in Germany after Schröder's close ties with President Vladimir Putin came under close scrutiny.

The Economics Ministry in Berlin disclosed last week that just before Schröder left office last November, his government issued a credit guarantee of €1 billion, or $1.2 billion, to Gazprom, Russia's state-owned energy company, to build the North Sea Gas Pipeline with two German companies.

Schröder was appointed chairman of the new company overseeing the construction of the pipeline shortly after leaving office, while the deal itself was clinched last September, just before Germany's parliamentary elections in which Schröder lost to Merkel, a conservative.

Lavrov said he had no idea if Gazprom - the world's largest gas company - would still take up the credit guarantee. "I know nothing about it," he said.

He did say, however, that Merkel supported the pipeline, which will cost over €10 billion to construct. "We wish to diversify the routes of energy exports," he said, adding that the project would lead to more energy security.

But he brushed aside any notion that the pipeline would in fact increase Europe's dependence on Russia for its energy, and that the energy relationship was a one-way street. "Energy security requires consideration for the interests of both energy suppliers and energy consumers," he said. "We depend on Europe for our exports and we also need stable and reliable demand."

Thirty-five percent of Russia's energy is exported, but exports account for 70 percent of Gazprom's revenues because Russia's domestic energy prices are subsized. Over 80 percent of Gazprom's exports are sold to Europe.

Flush with a large trade surplus because of record-high energy prices that has enabled Putin to pay off debt to the Paris Club of Western creditor nations, Russia has more confidently taken foreign policy initiatives.

These include the recent invitation to leaders of Hamas, the Islamic movement that won the Palestinian elections, to visit Moscow. Russia also offered to process uranium for Iran inside Russia in a bid to break the stalemate with the United States and the European negotiating group of Britain, France and Germany over Iran's nuclear program.

Lavrov said those initiatives were justified because Russia was not prepared to accept any "clash of civilizations" between the Western world and the Middle East. In barely veiled criticism of U.S. policy in Mideast, Lavrov said Washington's plans to democratize the region were obsessive.

"We have to take into account the overall energy needs of the world and the obsessions with democratizing the region overnight," he said. "We can't take sides in the conflict of civilizations. We want to help to bring both sides together. We want fair play. Russia's foreign policy is free of ideological considerations."

Lavrov insisted that Russia was pursuing an "unbiased" approach in the region that was crucial to global energy security. Even if all the ambitious plans are implemented to save energy, "the need by the world for energy supplies will not diminish," which is why a new concept of international relations was needed that involved Russia and Germany.

"There must be no going back to zero sum games or political games," he said. "We want to play in a team."