The State Department confirmed yesterday that Iraqi authorities have carried out their threat to move westerners to key industrial sites around Iraq in an apparent effort to discourage a U.S. attack.

Department spokesman Richard Boucher said U.S. officials have "credible reports" that some of the westerners have been taken from the Baghdad hotels where they were being held to "industrial installations" around the country. But he said officials could not confirm if any of those being transferred were among the 53 Americans known to be detained in Iraq.

A senior Bush administration official, speaking on the condition he not be named, said the action in Iraq was potentially more serious than that in Kuwait, where one American and 10 British citizens were reported to have been taken from their homes and detained, according to disclosures yesterday by U.S. authorities and the British Foreign Office.

"What is going on in Kuwait does not appear to be systematic," the senior official said. But the Iraqi transfer of westerners to the industrial sites "certainly is very troubling" because it will make it extremely difficult for the few U.S. officials in Baghdad to keep track of any Americans who may have been moved, the official said.

The one American and 10 British citizens were ordered out of their apartments in Kuwait City after occupying Iraqi soldiers ordered a Kuwaiti at gunpoint to tell where westerners were living, officials said. It was the first confirmation that the occupying Iraqi forces had moved into residential communities in the Kuwaiti capital in an effort to round up westerners.

British and U.S. officials said they had been allowed to visit the captives, all of whom are being held in Kuwait City.

The capture of the American in Kuwait City brought to 54 the number of Americans that U.S. officials believe are being detained in the two countries. This includes six Americans staying at a Baghdad hotel who until yesterday the U.S. Embassy did not include among those being detained.

Boucher also disclosed that 18 diplomats and their dependents from the U.S. Embassy in Baghdad had used their diplomatic status to depart Iraq for Jordan. Early in the crisis with Iraq, the State Department had insisted that diplomats not be accorded any travel privileges in Iraq not accorded private citizens, implying they would not use their diplomatic status to gain preferred treatment.

Asked whether the decision to have the diplomats leave reflected a change in U.S. policy, a State Department official said the United States had "pressured them every time" to give diplomats and private citizens the same travel privileges, but that the government of Iraqi President Saddam Hussein had refused to yield.

Unlike the Aug. 11 exodus of U.S. diplomats from Baghdad, when 10-year-old Penelope Nabokov, one of the initial hostages, was allowed to leave with the diplomats, no private citizens were allowed to accompany them, Boucher said.

Speaking to reporters in Maine, where President Bush is vacationing, White House press secretary Marlin Fitzwater said the U.S. government was "thankful" that the 18 had been able to leave Baghdad.

But he expressed concern that the whereabouts of many Americans remain unknown and that some of the westerners are being moved. "It does appear that citizens of all nations are being moved about in Iraq to unknown destinations," Fitzwater said. "Again, there are many nationalities involved but we don't know where they are being taken."

An estimated 13,000 citizens from the Western industrialized nations are believed to be in Kuwait and Iraq and barred from leaving.

John Lampl, a spokesman for British Airways, said a group of 63 Asian passengers and crew members who were on a Boeing 747 jet trapped in Kuwait after the Aug. 2 Iraqi invasion had been given permission to leave Iraq, where they had been taken by the military authorities.

But Lampl said 240 passengers and 70 company employees, mainly from Western Europe, the United States and Canada, could not be accounted for. "We know they have been taken from their original hotels in Kuwait but we don't know where they have been taken," Lampl said. "We don't even know whether they are in Kuwait or Iraq."

U.N. officials said yesterday that 75 of its staff members and dependents have left Baghdad and that the United Nations intends to remove its remaining 235 staff and family members from Iraq and Kuwait.

From Ankara, Turkey, Washington Post special correspondent Thomas Goltz reported that several employees of Bechtel International, the San Francisco-based construction company, were reported by their co-workers at a dam site in northern Iraq to have been taken to Baghdad by Iraqi authorities.

The Bechtel employees were acting as consultants for a $2.5 billion Turkish-Yugoslav venture to build a huge power station on the Khabur River when they were taken Monday from the town of Mosul.

"There were four Americans, and the German wife of one of them," said Zekiriya Cavusoglu, head of foreign procurement at the Mosul office of the Turkish firm ENKA. "The Iraqis collected them along with their passports at Mosul and took them to Baghdad."

Mike Kidder, a Bechtel spokesman in San Franciso, acknowledged that the company has employees in Iraq, but denied that any were in custody.

Staff writers David Hoffman and Keith Kendrick contributed to this report.