Iraqi troops in Kuwait surrounded the U.S. Embassy and the diplomatic missions of at least seven other nations yesterday, and Iraqi authorities blocked more than 100 American diplomats and their dependents who had fled Kuwait earlier from leaving Baghdad.

A handful of American officials, effectively isolated, remained at the U.S. Embassy in Kuwait in defiance of Iraq's order that all diplomatic missions be closed. European diplomats said Iraqi authorities had threatened to cut water and power to the missions and to use force to remove diplomats remaining at their posts.

The British Foreign Office said tanks were surrounding its embassy and that water and power had already been shut off, and Italy said three of its diplomats who had left Kuwait were detained in Baghdad.

A senior Iraqi military official said in an interview on Iraqi television that Iraq would close the embassies today.

"This is the last night, and after that there will be no embassies in Kuwait; diplomatic immunity will be stripped and there will be no delays," the official said. A U.S. official said last night that other countries had advised them they had received similar threats.

U.S. officials accused Iraq of reneging on earlier assurances that the U.S. diplomats and their families who had left the embassy in Kuwait and had traveled by car to Baghdad would be allowed to depart Iraq. Late Thursday night, however, U.S. officials in Baghdad were notified that Iraq had issued a new regulation, barring diplomats of any countries still maintaining embassies in Kuwait from leaving Iraq.

An Iraqi spokesman confirmed late yesterday that the government had decided to prevent male diplomats from leaving "until their countries complied with the order to close" but said that the families of those diplomats would be allowed to leave.

Iraq's squeeze on foreign diplomats came as the United States continued its massive military buildup in the Persian Gulf -- which included the arrival yesterday of a battleship armed with Tomahawk cruise missiles -- further raising tensions as the crisis moved into its fourth week.

State Department spokesman Richard A. Boucher indicated that the Iraqi troops occupying Kuwait were attempting to seek out some of the 2,500 Americans who are believed trapped in the country. He said the embassy staff there was having to guard its brief telephone conversations with Americans closely "because we know that the Iraqis are monitoring the embassy's local telephone calls in an attempt to locate American citizens."

He would not elaborate other than to say that the embassy had devised alternate methods of keeping the trapped Americans informed. An Arab guide who said he was spiriting foreigners out of Kuwait told Washington Post correspondent David B. Ottaway in Raghwa, Saudi Arabia, that Kuwait City was filled with Iraqi troops looking for foreigners. "If they catch any foreigners, they take them away. It's getting tough for them," the guide said.

The State Department sharply protested the detention of the diplomats and their dependents, calling it "another stark example of Iraqi duplicity." White House press secretary Marlin Fitzwater described it as "another troublesome element in the overall pattern of harassment and hostage-taking kinds of activities that {Iraqi President} Saddam Hussein has been engaged in."

"We've always tried to move the people out," an American official said when asked what the United States would do if Iraq tries to separate the diplomats from their dependents in Baghdad. Officials said the U.S. would continue to protest until all the Americans are allowed to leave.

The Americans who made the 19-hour automobile trip to Baghdad Thursday included a large number of dependents, including approximately 30 children and the embassy's Marine guards. All were ordered to leave Kuwait following the Iraqi order to close the Kuwait embassy. U.S. officials decided to withdraw "nonessential" personnel but to keep the embassy open.

Along with most other nations that had embassies in Kuwait, the United States has refused to recognize Iraq's annexation of the oil-rich country and has declared Iraq's order to close foreign embassies there "null and void." The Associated Press reported that troops had surrounded or were near the embassies of Britain, France, Japan, Norway, Sweden, Romania and Hungary in addition to the United States. It said Venezuela, the Philippines, India and Lebanon had closed their embassies.

Moscow has evacuated its citizens from Kuwait, including its diplomatic personnel. However, a Foreign Ministry official in Moscow said the Kremlin had no intention of cutting diplomatic relations with the Kuwaiti government and was keeping in close contact with it both through the embassy in Moscow and "through other channels."

The Soviet Union, with between 7,000 and 8,000 nationals in Iraq, said it will evacuate the children and spouses of its nationals working in Baghdad. Soviet officials said that Moscow's military advisers in Iraq did not participate in, or have prior knowledge of, the invasion. They said the advisers would remain in Iraq until their "contracts run out."

The day's events noticeably increased tensions at the State Department and among advisers to President Bush at Kennebunkport, Maine, where one said the U.S. diplomats in Kuwait are facing "a high degree of danger." A senior State Department official acknowledged a change in the atmosphere. "The mood in the seventh-floor crisis room is tense," said the official. "These {stranded} diplomats are the colleagues of the people here."

U.S. officials said the Bush administration was considering how to retaliate against against the latest moves. "We have several measures under consideration," was all that a State Department official would say when asked if the government would declare Iraqi Ambassador Mohamed Mashat persona non grata and order him out of the country.

Another official, also speaking on condition that he not be identified, said that it was doubtful that Mashat would be expelled "unless the Iraqis do something directly to the head of our mission" in Kuwait. U.S. Ambassador W. Nathaniel Howell and the other U.S. diplomats remaining with him in Kuwait were reported unharmed last night.

But officials conceded that the U.S. Embassy had been cut off from the rest of Kuwait City by a dozen Iraqi soldiers who took up positions around the walled embassy compound yesterday morning and blocked the embassy's entrance.

The battleship USS Wisconsin steamed through the Strait of Hormuz into the Persian Gulf yesterday, representing a major increase in naval firepower that could be brought to bear on targets in Iraq and Kuwait. The Wisconsin, whose 16-inch guns could reach Iraqi troop formations in Kuwait, is also carrying a full load of Tomahawk cruise missiles whose computer guidance systems have been reprogrammed to hit a broad array of Iraqi targets if called upon.

A Pentagon official disclosed that U.S. military plans for a worst case scenario in the confrontation with Iraq were dealt a setback this week when Egypt's President Hosni Mubarak turned down a U.S. request to deploy B-52 bombers to an Egyptian air base. The bombers would be available to strike Iraqi targets from there under several contingency plans available to the president, according to Pentagon sources.

Military officials said they did not know what reason Mubarak gave in turning down the request, but efforts were continuing to persuade the Egyptian to allow the deployment.A U.S. Navy official said a total of 60 warships are now deployed in the Persian Gulf area, Red Sea and Mediterranean Sea as part of the U.S. military buildup. On the ground in Saudi Arabia, about 40,000 U.S. troops will soon be joined by 45,000 Marines aboard a flotilla of amphibious assault ships en route to the region.

New departures announced yesterday included elements of the Army's 3rd Corps Artillery from Ft. Sill, Okla., the Pentagon said. And Gen. H. Norman Schwarzkopf, head of the U.S. Central Command in the Persian Gulf, was moving the remaining elements of his headquarters staff from MacDill Air Force Base in Tampa, Fla., to Saudi Arabia.

In Tehran, Iranian President Ali Akbar Hashemi Rafsanjani said yesterday that he had no objection to foreign forces pushing Iraq's army out of Kuwait, as long as they leave afterward, Reuter reported.

Turkey, which has been an escape route for refugees fleeing Iraq, said yesterday that it would consider closing its border with Iraq unless countries whose nationals are crossing into its territory provide transportation for its citizens. Jordanian authorities, who had said they would take similar steps because they were unable to cope with the thousands of refugees streaming in from Iraq, were still allowing them in.

Contributing to this article were staff writers Patrick Tyler in Washington and Dan Balz in Kennebunkport.