The US Congress' Armed Services Committee Chair, Senator John Warner, has proposed that the US ground contingent be placed under the power of a British commander.

The plans have outraged Republican senators who object to European command of American troops.

Defence correspondent Mark Laity: They always like their troops to be commanded by Americans

"Under no circumstances can we support the deployment of US soldiers under a foreign flag," wrote Senators Mitch McDonnel and Gordon Smith in a letter to President Clinton.

Overall command of the combined air and ground forces will still be placed under a US commander, according to Senator Warner.

The BBC Defence Correspondent, Mark Laity, says Washington wants as few US troops as possible to go to Kosovo, but faces the dilemma that it would then be impossible for the US to justify commanding them.

French Defence Minister Alain Richard said on Thursday the proposed force would be made up of five brigades. He said US troops would probably take part, while its command would come from Nato's ARRC rapid reaction force, under Leiutenant General Michael Jackson.

UK's "leading role"

According to US Army General Henry Shelton, the US goal is to keep ground force commitments in Kosovo to "the very minimum", up to a maximum of 4,000 troops.

"Our numbers could be very low, possibly as low as 2,000," General Shelton told the Senate Armed Services Committee in a private 2-hour briefing.

Meanwhile, the UK Foreign Secretary Robin Cook has committed British troops to a "leading role" in any Nato force sent to the war-torn province of Kosovo.

"We are willing, as a leading European power, to make a leading contribution," he told BBC Radio 4's Today programme, adding that it was too soon to predict how big that force would be.

Mr Richard saidthat Paris was working with its Nato allies, and principally Britain, on the creation of a possible Kosovo peacekeeping force numbering between 25,000 and 35,000 men.

Richard told a news conference that France was ready to contribute 5,000 ground troops plus 40 aircraft and ships. He said the proposed force would be made up of five brigades.

"Catch-22 situation"

In an open Senate hearing, the US Defence Secretary William Cohen said that any Nato intervention in Kosovo would be unwise without a "real" agreement between Belgrade and the Kosovo Liberation Army.

But he said there was a "Catch-22 situation": The participation of US troops could be necessary to guarantee the involvement of the Kosovo Liberation Army.

"They feel that we, in fact, by participating in some measure on the ground, would give them the confidence they would not be attacked by Serb forces," Mr Cohen said.

US troop contributions to a Kosovo force should be small in comparison to the European contribution because US forces will have the lead in any air strikes against Belgrade, he added.

General Shelton said the troops could be needed in the region for three to five years to enforce any interim peace accord, and a series of "benchmarks" would be set down to mark progress and consider when to pull themout.

He predicted that the Nato force would number up to 30,000 in total.