We are told that the possession of nuclear weapons - in some cases even the testing of these weapons - is essential for national security. But this argument can be made by other countries as well.

Let me remind you that nuclear disarmament is not just an ardent desire of the people, as expressed in many resolutions of the United Nations. It is a legal commitment by the five official nuclear states, entered into when they signed the Non-Proliferation Treaty.

From my earliest days I had a passion for science.

But scientists on both sides of the iron curtain played a very significant role in maintaining the momentum of the nuclear arms race throughout the four decades of the Cold War.

The present basic philosophy is nuclear deterrence.

At a time when science plays such a powerful role in the life of society, when the destiny of the whole of mankind may hinge on the results of scientific research, it is incumbent on all scientists to be fully conscious of that role, and conduct themselves accordingly.

So I ask the nuclear powers to abandon the out-of-date thinking of the Cold War period and take a fresh look. Above all, I appeal to them to bear in mind the long-term threat that nuclear weapons pose to humankind and to begin action towards their elimination.