SYRIA'S foreign minister yesterday offered to join militant group Hezbollah in its fight against Israel and said a regional war would be "most welcome" as more than 30 people in Israel and Lebanon were killed on one of the worst days since the conflict began.

Hezbollah launched a major barrage at northern Israel yesterday and a single missile killed 12 reservist soldiers in the kibbutz of Kfar Giladi in the Shiite militia's deadliest attack of the nearly one-month-old confrontation. Scores more were injured in numerous other attacks across northern Israel.

Meanwhile, Israeli air strikes killed 19 people in southern Lebanon, including six Lebanese soldiers, as fighting continued despite a US-French draft UN Security Council resolution to halt the hostilities.

Lebanon yesterday rejected the resolution and asked the UN Security Council to revise the draft to include a demand for the withdrawal of Israeli troops from southern Lebanon.

But as the attempts at diplomacy continued, Syria's foreign minister, Walid Muallem, defiantly trumpeted his country's support for Hezbollah and warned that Syria was ready for "the possibility of a regional war if the Israeli aggression continues".

"If you wish, I'm ready to be a soldier at the disposal of Sayyed Hassan Nasrallah [the Hezbollah leader]," he said.

He was speaking after crossing into neighbouring Lebanon in the first visit by a senior Syrian official since Damascus - under international and Lebanese pressure - ended a 29-year military presence there last year.

Asked if he feared the conflict in Lebanon could spill over into a regional war, Mr Muallem said: "Most welcome.

"If Israel attacks Syria by any means, on the ground, in the air, our leadership ordered the armed forces to reply immediately," he added.

Mr Muallem also lashed out at the draft UN resolution, describing it as a prescription "for the continuation of the war".

He said: "It's not fair for Lebanon, therefore it's a plan for the possibility of the eruption of civil war in Lebanon and nobody, nobody, nobody has anything to gain from that happening, except Israel."

Damascus has called up several reserve units in recent weeks and dispatched special forces and anti-aircraft units towards its border with Lebanon.

Syria has been jittery since Israeli jets buzzed Damascus early in the conflict and recently bombed Hezbollah positions and roads near the border.

Tensions soared on Friday, when 23 Syrian farm workers were killed by an Israeli air raid as they picked peaches in the village of Qaa in Lebanon's eastern Bekaa valley.

"This new massacre is a racist, fascist and terrorist act committed with American weapons," Syria's information minister, Mohsen Bilal, said.

Yesterday brought further death and destruction on both sides of the border, with Israel experiencing its worst day so far.

A Katyusha rocket fired by Hezbollah guerrillas hit a crowd of Israeli soldiers in Kfar Giladi, killing 12 of them and wounding ten others.

The attack was part of a barrage of 35 missiles in that area within half an hour that caused fires with huge plumes of smoke and damaged a synagogue.

An official from Kibbutz Kfar Giladi said he had warned the troops to take cover before the explosion, but that they had ignored him.

There were reports that a brigadier-general, Guy Zur, was among those wounded in the blast.

Eli Peretz, in charge of the local ambulance services, said: "An entire group was hit, some very severely.

Those lightly wounded fled in all directions. We evacuated the seriously wounded by helicopter. Since the beginning of this war, and in fact in all my years of service, I have never seen a worse incident."

Dan Ronen, the northern police chief, referring to the draft Security Council resolution, said: "I don't understand diplomatic processes, but I can tell you we have more very tough days ahead."

There were also reports that at least one person was killed and 30 were injured in rocket attacks on Haifa. The rocket strike posed a severe test to Israeli morale, bringing the Israeli death toll in the fighting since 12 July to 90.

This compares to an estimated total of 591 Lebanese killed by the Israeli army, but is a much heavier cost than the public expected when the government of the prime minister, Ehud Olmert, launched the war in response to Hezbollah's capture of two soldiers in a cross-border raid.

In a demonstration of the army's inability to limit the rocket fire, more than 140 Hezbollah rockets crashed into northern Israel, including in Nahariya, Tiberias, Carmiel, Safed and Shlomi.

In southern Lebanon, dozens of Israeli air strikes hit communities and roads, with some villages bombed continuously for half an hour, security officials said. Fighting on the ground also raged along a stretch of territory just north of the Lebanon-Israel border.

Six members of the Lebanese military were killed in two Israeli strikes and missiles also flattened a house in Ansar village, killing a man and four relatives, Lebanese security officials said.

A rocket fired by a pilotless aircraft blasted a van carrying bread near Tyre, killing its driver, according to civil defence officials. Another person was killed in Naqura.

The US-French draft resolution calls for a "full cessation of hostilities" but gives Israel the right to take "defensive" military action.

It also specifies that Hezbollah must be disarmed and the two captured soldiers returned. It does not demand that Israel withdraw its forces in advance of the deployment of an international force in southern Lebanon.

Israel has refrained from public comment, but privately the government is said to be satisfied with the draft.

In Beirut, Nabi Berri, the Lebanese parliament speaker, who represents Hezbollah in negotiations, said the draft resolution was unacceptable since it would leave Israeli troops in Lebanon and did not deal with Beirut's key demands: a release of prisoners held by Israel and moves to resolve a dispute over a piece of border territory.

The US national security adviser, Stephen Hadley, said that once a resolution was adopted by the United Nations, Washington wanted a second one establishing a peacekeeping force in days, not weeks.