As threatened, Iraq on Monday turned back a U.N. weapons inspection team that included an American. Hours later, the U.N. secretary-general said Iraq accepted his proposal for a three-member team to come to Bagh-dad to try to defuse the crisis.

However, the U.S. ambassador to the United Nations said that Baghdad had threatened to shoot down U.S. surveillance planes - a threat Ambassador Bill Richardson called an "irresponsible escalation" of the crisis over weapons inspections."This is a direct threat on the United Nations," Richardson told reporters at U.N. headquarters. "A direct military threat to the United Nations."

U.N. Secretary-General Kofi Annan said the three-member team would not negotiate whether American arms inspectors will be allowed to stay - a point U.N. officials insist is not negotiable.

The team's goal is "to discuss with the Iraqis a firm implementation of the U.N. resolution" permitting the inspectors to determine whether Iraq has destroyed illegal weapons, Annan said.

In Washington, White Housepress secretary Mike McCurry expressed support for Annan's initiative, but made clear the United States would not condone negotiations.

"They are not negotiating. They are there to make clear that Saddam must comply with Security Council resolutions," McCurry said.

The team includes Algerian Lakhdar Brahimi, the U.N. special envoy to Afghanistan; Emilio Cardenas, Argentina's former U.N. ambassador; and Jan Eliasson, a Swedish foreign ministry official. They were due in Baghdad late Tuesday or early Wednesday.

Iraq's refusal to allow American inspectors has deepened the crisis between the United Nations and Iraq, which has accused the Americans on the U.N. teams of being spies and trying to delay the lifting of economic sanctions imposed for its 1990 occupation of Kuwait. A U.S.-led coalition drove Iraq from the emirate in the 1991 Persian Gulf War.

Maj. Gen. Nils Carlstrom, the Swedish head of the U.N. monitoring office in Baghdad, said that a missile inspection team that included at least one American expert was told by Iraqi officials that inspectors from the United States were no longer allowed to work in Iraq.

After the incident, Carlstrom said the missile team and two other inspection groups sent out Monday morning returned to their headquarters at a hotel in the Iraqi capital. It was not clear how many of the seven American inspectors in Baghdad were involved.

Carlstrom said there were "no threats at all, and the only thing was that we were told that the Americans were not allowed, so the inspection was called off."

House Speaker Newt Gingrich said the message must be sent "that the United States will take whatever steps are necessary to enforce an ability to inspect." He said that "absolutely" included military strikes.

The use of force is opposed by Russia, France and a number of Arab states.