Dashing hopes of imminent UN action to end the war, Russia announced that it would table a rival proposal for a 72-hour truce because US-French efforts had stalled.

The Russian announcement came as Margaret Beckett, the Foreign Secretary, was flying to New York — despite the travel chaos — for a hoped-for vote on the US-French proposal for a reinforced UN presence in southern Lebanon to supervise an Israeli withdrawal.

“We do not have an immediate prospect of this [US-French] resolution being accepted,” Vitali Churkin, the Russian UN envoy, said after a meeting of the five permanent members of the UN Security Council.

He said that Russia planned to table a rival UN resolution calling for a 72-hour humanitarian pause to allow time for a full cessation of hostilities to be negotiated.

After a day of optimism, the diplomatic deal fell apart because Lebanon rejected the deployment of new UN troops with a robust mandate under Chapter VII of the UN Charter, allowing the use of force.

Israel, which has postponed plans to push deeper into Lebanon to give diplomacy a chance, has insisted that it would turn over its positions in south Lebanon only to a tough multinational force that could prevent Hezbollah guerrillas returning.

But the Lebanese Government, which includes two Hezbollah Cabinet members, said that it would accept only a traditional UN peacekeeping force of the type that has been in southern Lebanon for 28 years.

The breakdown showed that the basic issue of the war — the disarming of Hezbollah — had not yet been resolved.

John Bolton, the US Ambassador to the UN, acknowledged that there was still no agreement on a resolution to end the war. But he said that he still hoped for agreement today.

While all sides agreed that there should be a cessation of hostilities, negotiations have been repeatedly bogged down on the question of “sequencing”.

Lebanon has demanded an immediate withdrawal of all Israeli forces, but Israel says that it will not leave unless a foreign force fills the power vacuum in southern Lebanon.

The proposed French compromise calls for a phased pullout by the Israelis synchronised with the deployment of the Lebanese Army alongside peacekeepers from Unifil, the UN’s monitoring force in Lebanon. They in turn would be reinforced by French forces and oversee a militia-free buffer zone from the Litani river to the Israeli border.

The key paragraph in the draft text says: “Lebanese troops should start deploying in south Lebanon in co-ordination with Unifil as the Israeli forces start withdrawing between Lebanon and Israel.”

Diplomats said that a breakthrough was made possible in part by France’s apparent willingness to send troops to boost the UN force in Lebanon without waiting for a political settlement. The French were expected to lead a second, more robust, force of about 15,000 troops to secure the region.

Britain acted as a bridge between America and France. The first sign of a breakthrough came yesterday morning when Mrs Beckett returned to London from her holiday in France for an emergency meeting at the Foreign and Commonwealth Office on Lebanon.

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