There is a dawning crisis of confidence in London and Paris over the conduct of the UN special envoy to former Yugoslavia, Yasushi Akashi, whose negotiating efforts failed to stop the Serbian bombardment of Sarajevo or forestall the Croat recapture of western Slavonia from the Serbs.
The Netherlands and the Ukraine are believed to be unhappy about the risk to their troops deployed as part of the peace-keeping force.
"The perception that the UN is never going to authorise Nato action is causing concern among troop contributors like ourselves," one official in London said yesterday.
The French Foreign Minister, Alain Jupp, is said to have been "furious" over the lack of response to Serbian attacks. Mr Jupp is likely to become Prime Minister under President Jacques Chirac and the two men have let it be known that they want a change of course in the former Yugoslavia.
Mr Jupp is understood to have told the Foreign Secretary, Douglas Hurd, that the new French government will not tolerate "muddling along with the status quo." Britain will be happy to let France take the lead in pushing for a change in the rules of engagement.
The issue of the UN mission is now under review at the behest of the Secretary General, Boutros Boutros-Ghali. It is thought that the minimum measure acceptable to Paris is strengthened protection for French troops around Sarajevo.
British officials insisted that diplomatic efforts to gain a settlement through President Milosevic of Serbia were still alive.
Bosnia will be the top item on Mr Hurd's agenda when he arrives in Washington today for talks with Vice-President Al Gore and the Secretary of State, Warren Christopher.
Meanwhile the Croatian President, Franjo Tudjman, promised yesterday to withdraw all his troops from UN buffer zones in Croatia. Germany's leaders, who received Mr Tudjman in Bonn, said Croatia's leader would have to keep his promise if he hoped to count on continued economic aid.
Mr Tudjman told German officials his army would leave the three remaining UN demilitarised zones last night. But by 8pm, only a few hundred had pulled out - with the entire force of 1,220 still remaining in the UN Sector North. There were no reports of Serb withdrawals.
One Croatian commander told the UN he would not leave until Serb fighters did the same. About 2,400 Croatians and 1,900 Serbs moved into the zones after Croatia recaptured the western Slavonia region from the Serbs.
Mr Tudjman promised he would not use more force but added that he intended to regain all the Serb-held lands. He said his patience with the use of political means to get them back was "not unlimited."
Chancellor Helmut Kohl and the Foreign Minister, Klaus Kinkel, made it clear that economic aid and Croatia's partnership with the EU depended on Mr Tudjman's keeping his promises to rebel Serbs as well as his co-operation with the Muslim-led government of Bosnia.
"Croatia's behaviour is the key to further European Union co-operation with Croatia," Mr Kohl said.