The United Nations Conference on Disarmament on Tuesday launched negotiations to stop the production of nuclear bomb-making materials after Israel gave in to American urging and dropped its effective veto.

But a government statement issued in Jerusalem said Israel still had "problems of principle" with such a treaty and stopped far short of any commitment to open a top-secret reactor widely believed to be a bomb plant.The pact, expected to take years to complete, is viewed as the next step in multilateral nuclear disarmament following the Comprehensive Test Ban Treaty banning under-ground blasts.

Israel's ambassador Yosef Lamdan relayed the decision to the current chairman of the 61-member forum in Geneva, which has been trying to get the talks back on track for three years.

All five official nuclear powers - Britain, China, France, Russia and the United States - are members of the Conference on Disarmament, as are India, Pakistan and Israel.