Vice President Bush sought to reassure NATO allies today that the administration's Strategic Defense Initiative is aimed at strengthening rather than doing away with the concept of nuclear deterrence that has been the cornerstone of postwar alliance defense strategy.

"Our objective is to strengthen deterrence, enhance the stability of both the Western Alliance and East-West relations and help ensure the peace of the world," Bush said.

Bush also repeated the administration's belief that a new round of talks on international trade should be held -- a proposal that was rejected by France during the economic summit in Bonn in May.

Bush's remarks in a speech to the International Institute of Strategic Studies here, came on the last day of an 11-day European tour that took him to seven NATO capitals.

The trip originally was billed in Washington and Western Europe as a sales tour to promote SDI. But events, including the hijacking of a U.S. airliner and the holding of 39 American hostages for 17 days in Beirut and the recent series of terrorist bombings, turned its focus to gaining support for U.S. counterterrorism measures and trying to coordinate a western response.

During a day and a half of discussions with Prime Minister Margaret Thatcher and her government, as well as with other governments an opposition leaders, Bush said, he had found "unanimous . . . enthusiasm" for cooperation in a "wide range of areas," including preemptive measures and intelligence sharing.

"The governments of the United Kingdom and the United States of America declare their determination to work together with all like-minded states in combating this evil," Thatcher, standing with Bush, told reporters outside her residence.

Britain, however, declined to join the United States in ordering legal and diplomatic measures to isolate Beirut International Airport and crack down on Lebanon immediately. Thatcher, according to a top aide, told Bush she wanted to consult with other Western European governments before taking steps such as the withdrawal of landing rights for the four weekly Middle East Airlines flights from Beirut.