Mediators demand Serbs withdraw today: UN Secretary-General may be forced to make decision on air strikes if troops remain on Mount Igman

The co-chairmen of the Geneva peace talks last night gave the Bosnian Serbs an ultimatum to withdraw all their forces from Mount Igman, above Sarajevo, by mid-morning today, a deadline that could mark a turning- point in the negotiations. Lord Owen and Thorvald Stoltenberg told the Bosnian Serb leader, Radovan Karadzic, that his men should complete their withdrawal to the satisfaction of UN monitors. They said the Bosnian government had pledged not to re-occupy the evacuated areas.

'Dr Karadzic has been told in very clear terms by the co-chairmen that all his forces must leave the mountain,' said John Mills, spokesman for the negotiators. 'All of them should be off the mountain by mid-morning.'

The United States warned yesterday that continued occupation of Mount Igman and Mount Bjelasnica could trigger Nato air strikes. And a UN spokesman said logistical arrangements were in place for possible air attacks by Western forces and were being tested.

Mr Mills said UN officers had monitored the departure of some Serbian units, but others remained in place. Dr Karadzic said after the meeting: 'We are withdrawing.' He said two routes were open to humanitarian convoys. Clear precedents exist for what Lord Owen and Mr Stoltenberg may do if the Serbs do not comply. In previous negotiations they indicated that if talks could not go on because of the actions of one party, they would refer the matter back to the UN Secretary-General, Boutros Boutros-Ghali, and the Security Council.

Such action would identify the Serbs as the obstacle to peace talks, pointing to their presence on Mount Igman, and turning the question of decisive action over to the Secretary- General. Diplomats were debating yesterday as to whether Mr Boutros- Ghali can order air strikes against Serbian positions or whether he should consult the Security Council.

In either case the ultimatum represented a gamble by the mediators in their efforts for a resumption of talks after a break of 10 days.

Bosnia's President, Alija Izetbegovic, again refused to return to talks until the Serbs withdrew, effectively blocking any progress. Although military leaders have signed an agreement and all three sides agree on constitutional principles, difficult talks still lie ahead on the definition of borders of the future Muslim, Serbian and Croatian states within a state. Yesterday Mr Izetbegovic said he was running out of patience: 'We are willing to stay one or two more days, but then we will return to our Bosnia.'

The departure of the Bosnian government officials would end the talks, although conference officials believe all sides see the point of continuing negotiations.

Lord Owen is said to be furious over media criticism that he has pressed the Bosnian government to accept the partition of Bosnia and the division of Sarajevo. Yesterday he told his spokesman to denounce commentaries in the Washington Post which compared him to Neville Chamberlain. The paper described Lord Owen as 'the personification of the West's broad diplomatic failure and moral surrender' and called on him to resign.

The latest report to the Security Council by the co-chairmen, made public last weekend, states that they have vigorously argued against Serbian proposals for dividing Sarajevo and that they believe no permanent solution can yet be agreed among the warring factions.