LONDON, AUG. 8 -- Britain today became the first foreign power to announce that it would join the United States in sending military forces to defend Saudi Arabia and other Arab states in the Persian Gulf against a possible invasion by Iraq.

Several other West European nations offered logistical support for the American-led initiative. Spain, Italy and West Germany said they would allow their naval and air bases to be used to help facilitate the transport of American troops and equipment to the region.

One key part of the U.S. strategy of creating a multinational force has been to persuade Arab and other Islamic nations to join in.

Although officials in Washington said Egypt and Morocco were potential members, both countries denied any agreement to participate. Egyptian President Hosni Mubarak has called for a pan-Arab force rather than promising that Egyptian forces will aid the U.S. effort.

The U.S. officials said that Pakistan, however, had made a commitment in principle to make available 5,000 troops to the multinational force.

France is expected to announce its next move on Thursday, but well-informed French officials said an active French role was not contemplated at this stage. They emphasized that the tough economic sanctions approved by the United Nations should be given a chance to compel an Iraqi withdrawal from Kuwait before the West takes the dangerous course of choosing the military option.

Britain's decision provides the United States with at least some multinational backing for an effort to contain Iraq that is overwhelmingly American.

British officials here said they expect that more European countries will commit themselves to help after NATO foreign ministers meet in Brussels on Friday to discuss the Iraq-Kuwait crisis. The Netherlands announced it was considering a role in the multinational effort.

Foreign Secretary Douglas Hurd announced Britain's decision after a three-hour emergency ministerial meeting that included an hour-long phone call between Prime Minister Margaret Thatcher and Saudi King Fahd, during which Fahd made a formal request for British military intervention.

Echoing President Bush's statements, officials here insisted that British forces would be deployed for the defense of Saudi Arabia and its Gulf neighbors, not for offensive action against Iraqi forces in Kuwait. Although they said the specific forces to be deployed had yet to be determined, Hurd and Defense Secretary Tom King told reporters that Britain's most likely contribution would be air and naval defenses rather than ground troops.

Thatcher and Bush discussed joint military action when they met in Washington Monday, officials said here, adding that the British decision to move ahead before other European governments decide on sending forces to the region was designed to demonstrate Thatcher's total support for Bush's tough stance against Iraqi leader Saddam Hussein.

Britain is the major supplier of aircraft and training to the air forces of Saudi Arabia, Bahrain, Oman and the United Arab Emirates, and analysts said British forces could readily be integrated with those smaller air corps. They said control of the air would be the crucial element in stopping an Iraqi move into Saudi Arabia or in eventually driving back Iraqi forces from occupied Kuwait.

The British maintain a squadron of 12 Tornado F-3 fighter jets at the Royal Air Force's Akrotiri Air Base in Cyprus, where a second squadron is due to arrive over the next few days for routine summer training exercises. Defense sources said one or both of those units could be deployed in the gulf.

Each British-made fighter is equipped with four Skyflash medium-range air-to-air missiles, four Sidewinder short-range missiles and a 27mm Mauser cannon. Other types of aircraft, including Tornado bombers, fighter planes or maritime patrol aircraft, could be sent as well.

Defense Secretary King said the planes would be supported by air defense systems, specifically Rapier anti-aircraft missile batteries. Each battery comes equipped with 13 missiles and can be transported by cargo plane or lifted by large helicopter. There were also unconfirmed reports tonight that Britain might send its Fifth Airborne Brigade to help defend the planes in case of an Iraqi ground attack.

It was unclear whether Britain planned to further strengthen its naval forces in the gulf. HMS York, a destroyer, is currently on patrol with a support ship, and two frigates, Jupiter and Battleaxe, are moving into the area to join them.

The effort to create a multinational force to rein in Saddam followed tough economic sanctions adopted by the U.N. Security Council Monday. One of the few nations that refused to enforce the embargo today was South Korea. South Korean companies have more than $1 billion in current and pending projects in Iraq and Kuwait, with about 1,200 South Koreans working in the two countries.

Correspondent William Drozdiak in Paris contributed to this report.