To defuse an escalating crisis, British Prime Minister Tony Blair and others have called for a "robust" force much larger than the 2,000-strong UN observer mission already in Lebanon.

Whatever force takes shape, Washington made clear that US troops will not be on the ground.

"We are looking at what kind of international assistance force makes sense, but I do not think that it is anticipated that US ground forces are expected for that force," US Secretary of State Condoleezza Rice told reporters Friday.

Rice said she had spoken with UN Secretary General Kofi Annan about a possible multinational force and discussions were underway with US allies to resolve key issues.

"The questions about what kind of force it is, what its command structure is, is it a UN force, is it an international assistance force, those are the discussions that are going on and I think are going to go on over the next few days," Rice said.

Any UN or international force would have to be strong enough to prevent the Shiite Hezbollah militia from operating out of southern Lebanon, she said.

"That's going to take a robust force."

An Israeli offensive against the militant Shiite group Hezbollah, launched in response to the kidnapping of an Israeli soldier, has left more than 352 people dead in 11 days.

The talks on a stabilization force came against the backdrop of rising violence, as Israel kept up its offensive against Hezbollah militants, sending armoured vehicles into south Lebanon on Saturday.

Former German foreign minister Joschka Fischer has said it would make "little sense" to deploy a bigger UN force in Lebanon to stabilize the country.

"Another Blue Helmet mandate will make little sense. Only a robust force with a robust mandate could perhaps achieve something positive. But the risks are enormous," Fischer recently told Die Zeit newspaper.

In New York, the US ambassador to the UN, John Bolton, said talks on a stabilization force had to address "broad questions" about the contingent's authority to confront and disarm Hezbollah as well as its relationship to the existing UN mission and the Lebanese government.

Bolton warned against creating a new mission that would simply add a new layer of UN bureaucracy in the region.

"And while hardly an interim force, it is reasonable and responsible to ask how a new force would differ from and be more effective than UNIFIL (the UN Interim Force in Lebanon)," Bolton said on Friday.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.