The advice reflects a deepening mood of resignation among the allies that, as Serb forces tighten their hold on Sarejevo, the military position of the Muslims has become hopeless, and that surrender may be forced upon them in a matter of weeks. It is also a final signal to the Bosnian government that it should abandon any hope of last-minute military intervention by the West.
'We are explaining to them that they have only two alternatives: to continue fighting in a deteriorating situation or start negotiating,' a senior Western official confirmed in Washington.
But even as the advice was issued, there were suggestions that the Serbian leadership was considering boycotting the talks, preferring to crush the Muslims militarily.
The Geneva talks, which the Bosnian government agreed to attend on Tuesday if today's ceasefire in Sarajevo holds, are based on a joint Serbian-Croatian plan that would partition Bosnia's territory into Serbian, Croatian and Bosnian Muslim mini-states.
'I question whether a meeting at this juncture could be called negotiations without misusing the word,' the Bosnian Serb leader, Radovan Karadzic, said in a letter to the co-chairmen of the talks, Lord Owen and Thorvald Stoltenberg. He suggested instead that the talks should be postponed indefinitely.
This possibility, in the light of the White House position, has caused an outcry and increased pressure on the Clinton administration for action.
In an open letter drafted by Representative Frank McCloskey, a Democrat, a group of 78 Congressmen urged Mr Clinton to use force to break the siege of Sarajevo. 'We are writing this open letter to appeal to you to take the immediate action necessary to save the 380,000 residents of Sarajevo from a humanitarian disaster of immense magnitude.' It asked the President to issue a 72-hour deadline for the Serbs to cease fire, withdraw from positions surrounding the city and remove their blockades, or face action by Nato warplanes.
The US Secretary of State, Warren Christopher, caused uproar last week when he all but admitted that Washington had given up hope of helping Bosnia to repel the Serbian and Croatian onslaught. The US, he told journalists on Wednesday, is 'doing all it can consistent with our national interests'.
The American Jewish Congress, in a letter to Mr Clinton, criticised Mr Christopher's remarks. 'The cold indifference to the massive human catastrophe in Bosnia expressed by your administration's policy constitutes a betrayal of fundamental American values, no less than America's national interest,' the group said.
On Thursday, President Clinton attempted to dress up Mr Christopher's remarks in more positive language. 'That is not true that we are giving up on it . . . We have aggressively committed ourselves to the process in Geneva,' the President insisted. 'We are continuing to work with the Europeans on other options.'
Although Mr Clinton has endorsed lifting the arms embargo on Bosnia and using air strikes to help to protect Muslim enclaves, he has in effect stopped pushing for that strategy in the face of European opposition. The remaining options appear to be those already agreed and implemented: economic sanctions against Serbia and enforcement of the Bosnia no-fly zone. The only possible new initiative may be to activate allied plans to provide Nato air cover for UN forces protecting the six remaining 'safe havens' in Bosnia.
Should a peace plan arise out of Geneva, the US may once again have to decide whether to send ground troops to the region. President Clinton has said only that America would 'participate' in the implementation of any truce.