Western diplomatic defiance of Iraq's seizure of Kuwait weakened Friday when Germany and Belgium announced their last envoys had left the occupied nation. A jetliner carrying 257 evacuees from Kuwait and Iraq landed in North Carolina.

The Pan Am jet, the first U.S.-chartered flight in nearly three weeks, landed Friday afternoon at Raleigh-Durham airport with 123 American citizens, six Canadians and others of unknown nationality.About 100 of those on the flight were under 13, including a few infants, officials said.

Also Friday, a French news magazine reported that the U.S. military has drawn up plans to free Kuwait and defeat Iraq in an attack next month. A group of Iraqi exiles said Saddam Hussein is already considering withdrawing from the emirate Iraq overran Aug. 2.

Iraq, meanwhile, said it may stop Soviet detainees from returning home if they have knowledge of Iraqi weapons systems. The evacuation began Sunday and Iraq has promised to let at least 2,000 Soviets leave.

U.S. Defense Secretary Dick Cheney plans to ask Soviet officials next week for intelligence data on the Iraqi military, which was armed largely by the Soviet Union.

There were signs that Western impatience with the standoff was growing and that the U.S.-led forces arrayed in Saudi Arabia and elsewhere in the region could be sent to war to force Iraq from Kuwait.

Pentagon sources said a Marine amphibious force was planning a practice assault on the Arabian coast as a trial run for a possible U.S. invasion of Kuwait. A French magazine reported Friday that U.S. military officials have drawn up an offensive plan against Iraq.

The U.S. forces in the gulf area now total more than 200,000, including elements of two armored cavalry units that arrived this week, the Pentagon sources said. Officials indicated the buildup may be winding down.

The largest weapon used so far against Iraq has been the trade embargo imposed by the United Nations.

British Prime Minister Margaret Thatcher told her Conservative Party to be prepared for war if those sanctions fail.

The 5,000 delegates applauded when Thatcher said Iraqi President Saddam Hussein must face war crimes charges, pay reparation for the devastation of Kuwait and be denied the power to mount new attacks.

The French magazine L'Express reported that U.S. military officials have drawn up plans to free Kuwait and defeat Iraq in a four-day war in November that would destroy Saddam's armed forces.

L'Express said it obtained an outline of the plan from an unidentified adviser to Defense Secretary Cheney. The weekly publication is a general news magazine, similar to Time or Newsweek, and has one of the largest circulations in France.

L'Express said U.S. planners estimated the offensive might cost 20,000 American lives. It gave no estimate for dead of other nations.

U.S. officials refused to comment, in line with Pentagon security rules.

Saddam has claimed that Kuwait is historically part of Iraq and has said repeatedly that Iraq will never withdraw.

However, an Iraqi opposition party-in-exile said the Iraqi ruling Arab Baath Socialist Party has circulated a questionnaire asking prominent members whether they believe Iraq should pull out.

The claim by the Kurdistan Democratic Party-Iraq could not be independently confirmed. If true, it would represent an unprecedented quest for consensus by Saddam.

Saddam has declared Kuwait to be Iraq's 19th province, and Iraqi forces have encircled and cut off supplies to diplomatic missions since ordering them closed on Aug. 24.

Diplomats from nations that oppose the Aug. 2 invasion have tried to hold out but are slowly abandoning the embassies for lack of food and intolerable living conditions. Electricty and water have been shut off to most of them.

In Bonn, a German Foreign Ministry spokesman said the last diplomats in the German Embassy drove from Kuwait to Baghdad on Thursday. ZDF television, a German station, said the group included the ambassador and his wife, along with three staff members.

The Foreign Ministry official, who spoke on condition of anonymity, said they had run out of food.

Belgian officials in Brussels said their remaining two diplomats also left for Baghdad Thursday.

That leaves the Americans, British, Canadians and French as the only holdouts among Western missions.

In other developments:

-Saddam Hussein told Iraqi children that President Bush and the U.N. embargo on Iraq have deprived them of milk and sweets, but urged them to do without candy to maintain their pride and dignity. The speech, marking Iraqi Children's Day, was read by an announcer on Baghdad radio and television.