Nato ambassadors are gathering for an emergency meeting to discuss America's threat to pull its forces out of United Nations-authorised peacekeeping missions.

Washington is furious about the setting up of the International Criminal Court, which it says could lead to malicious prosecutions of American soldiers.

As a sign of its determination on the issue, it used its veto on the UN Security Council on Sunday to block the renewal of the UN mission in Bosnia-Hercegovina.

US peacekeepers under UN control

Africa: W Sahara 7 Ethiopia & Eritrea 7 Asia: E Timor 81 Europe: Kosovo 555 Bosnia 46 Georgia 2 Middle East: Iraq/Kuwait 11 Jerusalem 3 TOTAL: 712

The Security Council put the renewal of the Bosnia mission - whose mandate officially expired at 0400 GMT on Monday - on hold for three days for talks to take place.

But if no solution is found, 1,500 UN police officers and hundreds of logistical staff will have to start packing their bags.

In the short term, that would mean the end of the UN mission to train a new Bosnian police force.

But the American UN Ambassador, John Negroponte, has already hinted that the involvement of US troops in peacekeeping operations of any kind could also be called into question.

The US stands alone in the council

The US has hundreds of troops worldwide in peacekeeping operations, including more than 500 in Kosovo.

Nato's top decision-making body, the North Atlantic Council, was due to meet in Brussels at 1400 BST (1300 GMT).

Nato spokesman Yves Brodeur said on Monday that, strictly speaking, the Nato-led stabilisation force, S-For, would not affected, because it did not need a UN mandate to remain in operation.

The world cannot afford a situation in which the Security Council is deeply divided on such an important issue

Kofi Annan

S-For, although endorsed by the UN, was set up under the 1995 Dayton Accord, which ended the Balkans conflict.

"There are a lot of people who have got different interpretations," he told Reuters. "But we get our mandate out of Dayton and we will continue to do our job."

The UK Foreign Secretary, Jack Straw, has already been in intense discussions with his American counterpart, Colin Powell, and other senior officials.

The ICC

Comes into being on 1 July and begins work early next year Will be based in The Hague 68 nations have ratified the treaty 100-plus nations have signed up and may ratify the treaty in the future China, India, Pakistan, Indonesia, Iraq and Turkey have failed to sign up to the treaty The US, Egypt, Iran, Israel and Russia have failed to ratify the treaty

He told BBC Radio 4's Today programme: "We are trying to allay their fears. The ICC statute makes crystal clear that the ICC would only be involved if there was a failure by national criminal jurisdiction to deal with a transgression by peacekeepers."

Following the American decision on Sunday, UN Secretary General Kofi Annan - who was present for the vote - appealed to council members to intensify efforts to resolve the dispute.

"The world cannot afford a situation in which the Security Council is deeply divided on such an important issue, which may have implications for all UN peace operations," he said.

Mr Annan said the premature ending of the UN mission would be seen throughout the Balkans as a lessening of international commitment to the region.

Mr Negroponte said Washington vetoed the resolution "with great regret".

"With our global responsibilities, we are and will remain a special target, and cannot have our decisions second-guessed by a court whose jurisdiction we do not recognise."