The disagreement concerns ultimate command and control of the air strikes and goes to the heart of the matter for US involvement in UN peace-enforcement operations. The Pentagon does not want to concede authority to anyone.
US officials contend that air strikes, by the US or any other air force, are authorised under Security Council Resolution 770, allowing nations to take all means necessary to allow shipments of food, fuel, medicine and other humanitarian aid. Mr Boutros- Ghali, in a letter to the US Secretary of State, Warren Christopher, maintains that because of the UN role in mediating a ceasefire and eventual peace in Bosnia, it is his job to decide when to order air strikes.
The Americans are consulting the Secretary-General over the command and control question before next Monday's Nato meeting, when a final military plan for the strikes will be drawn up.
It is possible air strikes may be called in the meantime under Security Council Resolution 836, which calls for UN forces to use force to protect UN peace-keepers in Bosnia. The Americans agree with Mr Boutros- Ghali that this resolution requires the UN force commander to ask for air strikes and for the Secretary-General to initiate them by informing the Security Council. But the Americans argue that his job ends there. They do not agree that Mr Boutros-Ghali then has continuing authority to control the air strikes.
Nato air strikes would be the first combat engagement by the 44-year- old alliance and the first missions in support of a UN Security Council resolution.
The second reason for delay is the continuing talks in Geneva under the auspices of the EC and the UN between the three parties to the conflict. As one Western diplomat said yesterday, no one wants air strikes to cut across the peace efforts by Lord Owen and Thorvald Stoltenberg.
According to the present schedule, no strikes are likely until early next week, unless the Serbian gunners move forward to tighten their hold on Sarajevo or fire on UN forces.
In the first case - new Serbian aggression - the US has said it would use Resolution 770 to counter such an offensive. In any case the US has said it intends to start bombing Serbian positions around Sarajevo unless the siege is lifted by early next week.
In the second case - the need to protect UN troops under fire - Mr Boutros-Ghali could find himself under pressure to initiate strikes under Resolution 836 between now and the beginning of next week.
If the strikes take place, the original idea of hitting single pinpoint targets, such as artillery pieces, if they are found firing on the Muslim-dominated 'safe areas', appears to have been overtaken by a much wider brief. 'The Nato planes would not necessarily engage in precision firing, nor necessarily attack the gun that fired,' said one diplomat. At this moment such tactical changes serve only to increase the threat against the Serbian gunnners.
ZAGREB - A UN spokeswoman said that the commander of UN peacekeeping forces in former Yugoslavia, General Jean Cot, had met a senior Nato officer yesterday to discuss the co-ordination of air strikes, Reuter reports.Reuse content