Iraq for the first time yesterday explicitly prohibited foreigners -- including a 10-year-old California girl and thousands of other Americans -- from leaving Iraq and Kuwait and told diplomats in Baghdad that their embassies in Kuwait City should be closed.

After days of vague and contradictory statements, Iraq officially shut its borders and barred departures by foreigners, with the exception of diplomatic personnel, who will be able to leave after a seven-day waiting period, according to U.S. officials.

The moves further increased Bush administration anxiety over the fate of 3,600 Americans in Iraq and Kuwait. State Department spokesman Richard Boucher said Iraq has listed four basic categories of foreign nationals -- visitors, permanent residents, diplomats and those being detained in the Al-Rashid Hotel in Baghdad -- and said only the diplomats could leave.

Until the invasion of Kuwait, resident foreigners were able to obtain exit visas within a day and until yesterday visitors were routinely allowed to depart.

Boucher and other officials insisted that even those detained in the hotel under armed guard were being "sequestered" rather than held hostage.

"These are people that were brought up from Kuwait," Boucher said. "We have unfettered access to these people. Our consul meets with these people every day," he said, "but they have just not been granted permission to leave."

A senior White House official, explaining the aversion to the word "hostage," said, "It was a very conscious and deliberate decision not to turn these people rhetorically into hostages because then they become hostages."

Calling them hostages, he said, "puts a whole different cast on the discussions going on because you are backing this guy {President Saddam Hussein of Iraq} into a very different corner. How can he allow them to go if the perception is he's letting hostages go and making a concession of that magnitude to the United States?"

Asked why the administration was not releasing the names of those held at the hotel, Boucher said, "Officially we release the names of people who are killed, captured in war, called hostages by their captors or identified by their relatives. If we started putting out these names, then we put them more or less in those official categories. And then you have the problem of the 3,000" Americans in Kuwait.

"Why should we treat the 38 different than the 3,000? Other than the fact they don't have room service, they're in the same condition. They can't get out of there."

State Department officials said the Iraqi government circulated a note in Baghdad to all foreign missions saying that, given the annexation of Kuwait, there was no need for any embassies in Kuwait City.

The note, one official said, told the foreign governments to "wind up your operations." He said the move came as no surprise and was a logical step after Iraq's announced annexation. "Our position is that we recognize Kuwait" as a sovereign nation.

Officials refused to release the precise wording of the Iraqi note, and it was unclear whether Iraq intended to enforce its position by physically shutting down foreign missions.

American businessmen who managed to get out of Iraq Wednesday told Washington Post staff writer Nora Boustany in Amman yesterday that they sensed no hostility but felt isolated after the airport was shut, the borders closed and international communication lines cut off from the rest of the world.

Frank J. Jiral, an executive with Brown & Root Inc., made it out of Iraq with four other Americans and a group of West Germans aboard a bus in a strenuous 18-hour journey covering 950 kilometers between Baghdad and Amman.

Americans remaining in Iraq were "looking for support and someone to take a chance" helping them leave, Jiral said.

"We had to find our own way out," said Frank Zurawel, an employee of Linker Equipment, as he checked out of his Amman hotel to fly to Tanzania for another job. "Any time you are detained, not a hostage, but detained, you can draw your own conclusion," he said, adding that he felt no anti-American sentiments from the Iraqis.

Western diplomats in Amman said the border now appears to be closed to westerners but open to Arab nationals, who were streaming out in cars packed with belongings.

Administration officials remained optimistic yesterday despite the latest Iraqi moves. White House press secretary Marlin Fitzwater said that there are hopeful signs in the situation.

"Americans are being treated like {other foreigners}. Their treatment is no different, which is a very good sign." Asked why the administration does not concede they are prisoners or hostages, he said, "The point is, we want to get them out. The best way to do that we think is to be cool. To sit tight. Trying to single them out or label them we don't see as helpful."

Another senior official said that despite the Iraqi policy, "in fact, we are getting some Americans out, quietly and unofficially some are coming out." Because of that and other considerations, he said, "the threshold of considering them hostages" has not been reached.

Other administration officials echoed a definition British Foreign Secretary Douglas Hurd gave to reporters in England yesterday. Hurd, discussing the estimated 3,500 British citizens in Iraq and Kuwait, said that since "no terms have been set {by Iraq} for their release . . . they are not technically hostages . . . but they're held against their will."

Although French President Francois Mitterrand said that one mission of the French fleet dispatched to the Persian Gulf would be to evacuate 420 French nationals in Iraq and Kuwait, U.S. officials said the Defense Department has received no specific orders regarding an evacuation plan.

For the relatives of those trapped in Kuwait and Iraq, there was an increasing sense of anxiety yesterday, however the predicament of their family members was characterized.

Connie Ogle said that it did not matter what U.S. officials call her father-in-law, Rainard Walterscheid, a drilling supervisor plucked from a Kuwaiti oil rig near the border and bused to Baghdad.

"I knew they weren't going to let them out. I think they're hostages," she said from Jacksboro, Tex. "The first day I thought there may be some confusion. The second I thought that something was wrong. The third I knew."

Vafa V. Fouroohi, whose father, Fred F. Harrington, of Redmond, Wash., also is in the hotel, agreed: "There's a fine line difference between detainee and hostage; we could name them either. If he's not free to leave it doesn't matter."

Boucher said U.S. officials had failed to obtain permission from Iraqi officials for Penelope Nabokov, the 10-year-old California girl released Wednesday from the Al-Rashid Hotel, to leave the country with a group of U.S diplomats and their families. The 10 members of the group had been told in Baghdad they could leave but were turned away at the border.

At least two other children are also known to be detained at the hotel along with their parents.

Kevin Bazner, his British wife, Dawn, their daughter, Elizabeth, 6, and 5-month-old son, David, were returning to Malaysia, where Bazner is the regional representative for a soft drink company, from a visit to Denmark when their British Airways jetliner was seized in Kuwait. They were later taken by bus to the Baghdad hotel.

"That whole plane was in the wrong place at the wrong time," said Virginia Bazner, Kevin's mother, from her house in Palm Desert, Calif. "Today is the day that the realization has hit me. I'm just exhausted." She said that the State Department called again yesterday to inform her that her son and his family were well.

"I asked if they could give them a message that we love them, that prayers are coming in from all over the world and that we want them home," she said.

Her mood was typical of relatives of the captives, whose emotions yesterday ranged from a wary hope for the release of their loved ones at any time to a growing fear that they could be long in the grip of Saddam.

"I think we're going to remain optimistic, but reality is coming home," Fouroohi said.

American companies with major work forces in Saudi Arabia said yesterday that they are beginning to move their workers out of the country. A Washington spokesman for Saudi Aramco, the state-owned oil monopoly, said it had begun to arrange charter airlines to airlift American workers and their dependents from the country starting this weekend. With a work force that includes about 10,000 employees and dependents, the oil company is the largest employer of Americans in Saudi Arabia.

In Seattle, Boeing Co. said it had borrowed a 747-400 scheduled for delivery to Northwest Airlines to send to Saudi Arabia to remove hundreds of Boeing dependents.

Staff writers Ann Devroy, Bill McAllister and Michael J. Ybarra contributed to this report.