The Bush administration conceded Wednesday that differences with France have stalled efforts for a U.N. Security Council resolution ending the Lebanon fighting. U.S. officials insist that any Israeli withdrawal from southern Lebanon should coincide with insertion of an international peacekeeping force to prevent a power vacuum.

US Assistant Secretary of State David Welch, right, with bodyguard in Beirut, Lebanon, 9 August 2006, after meeting with Fuad Siniora

Officials at the State Department had expressed hope earlier in the week that a Lebanon resolution could be approved in the Security Council by Thursday. But the timetable is now slipping, amid what they acknowledge are differences with France over the sequence of events that would bring about an end to the fighting.

The United States and France, which have taken the lead in U.N. Lebanon diplomacy, produced a draft resolution late last week that called for a full cessation of hostilities between Israel and Hezbollah.

But Lebanon and other Arab states objected to the initial text because it did not provide for an Israeli withdrawal from southern Lebanon.

Negotiations at the United Nations have since become bogged down over the sequencing of an Israeli pullout and the introduction of an international force that would supplement the deployment of Lebanese government forces along the Israeli border.

The border strip was controlled by Hezbollah after Israel dismantled a Lebanon buffer zone in 2000 and last month's outbreak of full-scale warfare was triggered by a Hezbollah kidnap raid into Israel.

At a news briefing, State Department Spokesman Sean McCormack said the United States is insisting in the U.N. negotiations that any Israeli withdrawal should coincide with the introduction of a "robust" international force so that Hezbollah, in the U.S. view a terrorist organization, cannot again provoke a crisis.

"We have stood firmly on the principle that you cannot create a vacuum there," he said. "Everybody agrees that Israel needs to withdraw as a part of the cessation of hostilities. Everybody agrees on that. The Israelis agree on that. But we are not going to replace something with nothing. Because if you do that, then you've once again put all the ingredients back for more violence, more instability, and the ability of a terrorist group to plunge the region into violence."

A senior official who spoke to reporters here said there were differences between the United States and France over the timing and sequencing of a security handover in southern Lebanon, and he pointedly refused to say those differences were being narrowed.

Spokesman McCormack expressed confidence that an international force capable of enforcing peace between Israel and Hezbollah can be assembled and put in the field in a relatively short time.

The United States has not ruled out a possible upgrade of the existing U.N. observer force in southern Lebanon, UNIFIL, as the core of the new peacekeeping mission.

But U.S. officials believe UNIFIL has been notoriously ineffective in its nearly 30-year presence in Lebanon and clearly prefer a force set up under a U.N. mandate but not under operational control of the U.N. bureaucracy.

Condoleezza Rice

Secretary of State Condoleezza Rice has been directing U.S. diplomacy from Washington and spoke to Israeli Prime Minister Ehud Olmert Wednesday after calls Tuesday to, among others, Lebanese Prime Minister Fuad Siniora and U.N. Secretary- General Kofi Annan.

Assistant Secretary of State for Near Eastern Affairs David Welch has been shuttling in the region for several days and met in Beirut Wednesday with Mr. Siniora and Lebanese parliament speaker Nabih Berri, a Shi'ite leader in close contact with Hezbollah.