CLINTON SIGNS BAN ON NUCLEAR TESTING.

Byline: Alison Mitchell The New York Times

President Clinton signed a treaty Tuesday that would ban all nuclear weapons testing and called on world leaders to take further steps to limit weapons of mass destruction. He also urged them to show ``zero tolerance'' for international drug smuggling and for terrorism.

In an address to the 51st session of the U.N. General Assembly, Clinton noted that it was the second year in a row that he had asked diplomats and world leaders to take a strong stand against what he calls the ``new threats'' of the post-Cold War era: Drug traffickers, terrorists and unsafeguarded weapons. ``Frankly, we have not done that yet,'' Clinton said.

``Real zero tolerance requires us to isolate states that refuse to play by the rules we have all accepted for civilized behavior,'' he said. ``As long as Iraq threatens its neighbors and people, as long as Iran supports and protects terrorists, as long as Libya refuses to give up the people who blew up Pan Am 103, they should not become full members of the family of nations.''

Clinton's annual visit to the United Nations was unusually brief - less than two hours long - and was coupled with a campaign rally later in New Jersey. It came at a time when the administration has said it would use its Security Council veto to keep Boutros Boutros-Ghali, who the United States says has not initiated enough reform at the United Nations, from serving a second term as secretary-general.

Nonetheless, the president and the secretary-general met and posed for a photo together, with Boutros-Ghali smiling and Clinton looking stiff and solemn. Later Clinton said the question of Boutros-Ghali's tenure did not arise ``because he and everyone else knows our position,'' adding, ``They know it's firm.''

Before delivering his address, Clinton used the same pen with which John F. Kennedy signed the Limited Test Ban Treaty in 1963 to sign the Comprehensive Test Ban Treaty. The comprehensive accord is intended to thwart the development of new generations of weapons by banning all nuclear explosions, underground and above ground, military or civilian, high yield or low yield.

The president called the treaty ``the longest sought, hardest fought prize in arms control history.''

An overwhelming majority of countries, including the five declared nuclear weapons powers - the United States, Britain, China, France and Russia - have now agreed to the treaty and the comprehensive ban. But India, which set off a nuclear explosion in 1974 and is believed to have a clandestine nuclear weapons program that it does not want to give up, has said it will not sign because the treaty does not set a date for the total elimination of nuclear weapons. Pakistan, which is also thought to have a covert nuclear program, has indicated that it will boycott the pact if India does.

The treaty will not go into effect for at least two years, and Clinton administration officials say they hope India can be brought around by then. Without assent by India and other potential nuclear states, the treaty and its enforcement measures will not enter into force although countries that do ratify it will be required to observe its provisions.

The president, however, said Tuesday that the signatures of the five declared nuclear powers, along with those of the vast majority of countries, ``will immediately create an international norm against nuclear testing even before the treaty formally enters into force.''

``Some,'' Clinton said in a reference to India, ``have complained that it does not mandate total nuclear disarmament by a date certain. I would say to them, do not forsake the benefits of this achievement by ignoring the tremendous progress we have already made toward that goal.''