NATO ambassadors are consulting with their capitals about a compromise proposal aimed at ending a deadlock over planning for Turkey's defense in case of a war in Iraq. The impasse has sparked one of the most serious crises in the alliance's 54 year history.

For three days, the ambassadors have been trying to break the deadlock over a U.S. proposal that would allow NATO to draw up contingency plans to protect Turkey in the event it is attacked by Iraq.

France, Germany and Belgium have blocked any such move, arguing that it would put NATO on a war footing while diplomatic efforts are under way to resolve the Iraq crisis peacefully.

Turkey has formally requested help from its allies, saying that its territorial integrity would be threatened if war were to break out.

The United States asked NATO last month not only to start planning to send anti-missile systems and surveillance aircraft to Turkey. It also wants the alliance to protect U.S. bases in Europe and replace American troops in the Balkans who may be deployed to Iraq in case of a war.

France, Germany and Belgium also say approving those requests at this time would imply an acceptance of the inevitability of war, although Germany has already assigned hundreds of troops to protect U.S. bases on its territory.

NATO Secretary-General George Robertson has tried to break the deadlock by offering a compromise proposal that concentrates exclusively on allowing NATO military planners to adopt measures to protect Turkey in case it is attacked.

The ambassadors discussed that proposal and asked for time to refer it to their governments. They are scheduled to meet again later in the day.

NATO officials say they cannot be sure that the three holdouts will accept the compromise proposal. They note that France and Belgium have said publicly that they would rather wait until Friday before making a decision. That is the day the chief U.N. weapons inspectors will report to the Security Council on Iraqi compliance with the resolution authorizing the inspections.

The dispute that pits France, Germany and Belgium against the 16 other allies, has led to NATO's worst internal rift in years. Secretary of State Colin Powell said Tuesday that the alliance is breaking itself up because it will not meet its responsibilities to plan for the defense of one of its members.