UNITED NATIONS, AUG. 17 -- The speaker of Iraq's parliament declared today that Iraq would not release citizens of "aggressive nations" until the threat of war against his country ends, the first time that Baghdad has clearly stated its intention to detain indefinitely thousands of the foreign nationals trapped in Iraq and Kuwait. He also said the detainees would be housed in military as well as civil installations.

The statement by National Assembly Speaker Sadi Mahdi came shortly after the U.N. Security Council called on Secretary General Javier Perez de Cuellar to take all "appropriate" steps to gain the release of the more than 1 million foreign nationals caught in the two countries since Iraq's Aug. 2 invasion of Kuwait.

In Iraq, 35 Americans who had been held by Iraqi officials at a Baghdad hotel were whisked to a secret location and denied access to U.S. officials or the press. The move reinforced fears among senior U.S. officials about what the government of President Saddam Hussein plans to do with the estimated 3,000 Americans still in Iraq and Kuwait.

"The people of Iraq have decided to play host to the citizens of these aggressive nations as long as Iraq remains threatened with an aggressive war," Mahdi said in a statement carried by the official Iraqi News Agency.

"This measure will remain in force until such time as tangible and sufficient guarantees are forthcoming from the people of Iraq that the danger of oppressive aggression has passed," he said.

He also singled out the U.S. government, which has taken the lead in organizing a worldwide military and economic effort to isolate Iraq, for what he called "going out of their way to take hostile and unjust stands toward Iraq."

Mahdi said that Westerners would be held in facilities throughout Iraq, including places belonging to the armed forces, the Ministry of Oil and the Ministry of Military Industrialization. He said this would be done "so they are assured of the appropriate housing requirements."

The State Department had no comment on the Iraqi statement. An official said the United States does not want to reply "to all the different statements" about the Americans and other foreigners but rather will try to "keep working" to get them out. The deputy chief of mission in Baghdad, Joseph Wilson, has had almost daily contacts with the Iraqi Foreign Ministry over the status of Americans in Iraq.

At the United Nations today, U.S. Ambassador Thomas R. Pickering said that the 15 Security Council members had agreed unanimously that "the secretary general should become immediately engaged in dealing with this tremendously difficult crisis involving the foreign nationals." For the time being, Pickering said, the council "is leaving to his good judgment how he does it."

Perez de Cuellar, who is on a trip to Latin America, is not scheduled to return here for about 10 days. His aides in the U.N. Secretariat said they did not know whether he would come back sooner or what action he might take to attempt to induce Saddam to release the foreigners.

However, U.N. officials added, Perez de Cuellar is clearly on notice that the members of the world body want him to come up with some plan of action very quickly.

More than 16,000 people -- most of them Egyptians -- fled to Jordan from Iraq and Kuwait today, and nine foreigners, including three Americans, bolted across the Kuwaiti desert to safety in Saudi Arabia. The three Americans, who feared being rounded up in Kuwait, disguised themselves as Arabs to make the trip.

Although everyone at the United Nations has been careful to avoid using the word "hostage" in official public statements, that term clearly is on everyone's mind. British Foreign Minister Douglas Hurd said today on ABC's "Good Morning America": "We haven't had any particular demands from the Iraqis about them, so I suppose in that sense they're not strictly hostages. But . . . I don't think there's much point in quibbling about the words."

State Department officials said they believed the 35 Americans, 24 of whom were taken from Kuwaiti hotels during the Iraqi invasion, had been moved to another hotel in Baghdad. The officials said they based that belief on the refusal of Iraqi officials to allow U.S. diplomats to enter the Melia-Mansour Hotel, the only major hotel in the capital to which the American Embassy personnel were denied access.

Iraqi officials told U.S. diplomats that the 35 were safe and that they had been moved from the Hotel al-Rashid "because the hotel has been overrun by the media," said State Department spokesman Richard A. Boucher.

ABC correspondent Ted Koppel, who had been invited into Baghdad by the Iraqi government, was at the hotel Thursday and broadcast glimpses of its interior despite a government ban on such photography.

Boucher, however, scoffed at the Iraqi government's explanation of the move, saying it was not credible.

President Bush, who is vacationing in Kennebunkport, Maine, said today before playing a round of golf, "I don't think anybody ought to be moved against their will."

White House press spokesman Marlin Fitzwater said Iraqi officials have said the 35 Americans are safe but that the administration considers the move "a matter of serious concern."

He said that American consular officials had gone to the Hotel Rashid Thursday night to check on the Americans detained there and were turned away. The U.S. officials were told the Americans had been moved to another location. The Iraqi Foreign Ministry refused to give U.S. officials further information on their location. Fitzwater said there was some indication that Iraqi officials wanted to keep the Americans away from the press, which had been successful in making contact with them.

Since Thursday, when Iraq ordered the 2,500 Americans and 4,000 British stranded in Kuwait to assemble in two separate hotels, there has been a sharp rise in concern here that Iraq may be planning to use the foreigners as hostages against the worldwide demand that its forces leave Kuwait.

Fitzwater said the order for Americans in Kuwait to report to a hotel in Kuwait City or be rounded up by the Iraqi military had produced some confusion. Five or six Americans reported to the hotel, he said, but the hotel had no knowledge of the order and no accommodations for the Americans. Fitzwater said he believed the Americans had returned to their homes. He said there is no evidence that Americans are being rounded up.

In addition to the Security Council's action today, Italy, acting on behalf of the 12 members of the European Community and several other countries, called on Perez de Cuellar to intervene in the detainee situation.

Secretariat members said Perez de Cuellar, who was in Lima, Peru today, has not sent any instructions about approaching Iraq. Several speculated that he might sound out the Iraqis about the possibility of sending an emissary to Baghdad or even going there himself. However, others said there have been indications that Saddam will refuse to receive a U.N. emissary.

The problem, many diplomats acknowledged, is that the United Nations never has had to deal with a problem of this type throughout its 45-year history. The vast number of people potentially at risk means that the closest thing to a precedent -- Iran's 1979 seizure of dozens of Americans in Tehran -- offers few clues as to how the organization might proceed this time.

Diplomatic sources said that there appeared to be differences within the Security Council about the best tactical approach.

The sources said that the United States, while not unmindful of the danger to the detainees, appears to believe that putting too much public emphasis on their plight could encourage Saddam to believe that he can use them as bargaining chips to neutralize the economic sanctions and military buildup being employed against him.

But Britain, the main force behind today's council action, believes that "it is necessary to express very serious concern about what is happening," according to its U.N. ambassador, Sir Crispin Tickell.

Tickell said his government decided the situation was too chaotic and perilous to wait longer after Thursday's incident "when 4,000 British subjects were told to report to a hotel in Kuwait with room for 400. When those who complied got there, no one knew they were coming, and no arrangements had been made for them."

He said the confusion and lack of information about what is happening in Kuwait and Iraq had caused council members to agree that "it would be wise to leave to the secretary general the choice of means. He is very experienced and has been very successful in delicate diplomatic missions in the past."

Also today, the Security Council heard a report from its subcommittee monitoring compliance by the United Nation's 159 members with the council's Aug. 6 resolution imposing economic sanctions against Baghdad and Iraqi-occupied Kuwait. Since the members have until Aug. 24 to report the measures they are taking, council sources said it is too early to tell whether its boycott is being implemented successfully.

Staff writers Dan Balz in Kennebunkport, Maine, and Bill McAllister in Washington contributed to this report.