BRUSSELS, Belgium -- The NATO allies received strong backing from U.N. Secretary-General Kofi Annan for their threat to use military force to help bring about a political settlement in Kosovo.

In a speech to NATO ambassadors at their Brussels headquarters, Annan recalled "the lessons of Bosnia" and said the international community must use the "combination of force and diplomacy that is the key to peace in the Balkans."The notion that state sovereignty was sacrosanct should not prevent it from intervening, he told NATO's North Atlantic Council. The world community should have "no illusions about the need to use force when all other means have failed."

"We may be reaching that point once again in the former Yugoslavia," Annan warned.

The international community had to be ready to apply the lessons of Bosnia "practically and emphatically" in situations "where horror threatens," he told the 16-nation military alliance.

In Kosovo, he said, "horror is no longer threatening, it is present."

Annan was making the first official visit to NATO headquarters by a U.N. secretary-general.

Yugoslav security forces are fighting ethnic Albanian separatist guerrillas in Serbia's Kosovo province, where some 2,000 people were killed and a quarter of a million made homeless last year.