Doubts remained as to whether the agreement would be respected any more scrupulously than dozens of previous accords. The United Nations special envoy, Yasushi Akashi, said: "We finally managed to agree on a comprehensive cessation of hostilities." He added: "I am proceeding with General Rose [the UN military commander in Bosnia] to Pale to have [the Bosnian Serbs] sign an identical agreement."
Mr Akashi, arrived in Sarajevo expecting to sign the deal with the Bosnian government at noon; but objections to minor changes by both sides meant the signing ceremony had to be postponed for an urgent telephone conference with Pale.
The officials would not detail the contentious points, but they are believed to include the government's request for specific language on the demilitarisation of the six UN "safe areas", including Sarajevo, which yesterday marked the thousandth day of siege.
Under the agreement, which should supersede a four-month ceasefire that began on Christmas Eve, the warring factions are to withdraw their troops from frontline positions, while the UN deploys peace-keepers in the enlarged no man's land to monitor compliance with the truce.
However, it seems few technical details - such as the scale of such a retreat - are addressed in the draft document, which implies that lengthy negotiations will be necessary before the first soldiers pull back. The idea, though, is to create and cement a pause for peace that will concentrate minds on the need to find a political settlement.
Such hopes are likely to be somewhat dampened by the difficulties in persuading the parties to accept, even on paper, a basic assertion that they are willing to stop fighting. The UN, having spent the past week in ceaseless negotations, is reported to have told both sides that it will wash its hands of the process if they do not sign on the dotted line this weekend.
And, if the many protestations of good faith made over the past week in Pale and Sarajevo do not bear fruit, it is hard to see what else Mr Akashi can do. "I think it will work," said a UN official familiar with the negotiations. "After all, everybody needs a breather before the spring."
And there's the rub. Most observers are fairly confident the fighting will indeed stop - as it usually does during the bitter, snowbound winter - but few are betting on the success of the political, constitutional and territorial talks that are to follow. It is telling that the agreement put forward yesterday contains not a single reference to "Bosnia-Herzegovina".
General Ratko Mladic, the Bosnian Serb commander, told the UN he would not sign anything that referred to the country he is fighting over. He even balked at a reference to "BHC" - UN shorthand for its Bosnia-Herzegovina Command.
The Serbs, with reason, have proved more enthusiastic than the government in discussing the deal. Although Pale fears its enemies will use the pause to rearm, the deal more or less freezes the front lines as they are - that is, with Serb forces holding more than 70 per cent of Bosnia, rather than the 49 per cent to which they are entitled under the international Contact Group peace plan.
In theory, both sides should withdraw from their frontline trenches, allowing the UN to deploy peace-keepers to monitor the truce and even to patrol no man's land. But sources say no technical details have been agreed - for example, how far troops shouldwithdraw to achieve a separation of forces.
"It doesn't actually commit them to much beyond agreeing to agree to talks," one UN official said. The possibilities for disagreement over how far soldiers must retreat, at different points along the 1,200km front line, for example, should occupy beleaguered UN negotiators for many hours. And all that comes before the parties even begin to talk about a settlement.Reuse content