The risk of nuclear escalation in a future Mideast war has seriously increased now that Pakistan - though it won't admit it - has apparently developed the capability of producing atomic weapons.

Pakistan joins the ranks of three other nations - Israel, India and South Africa - that have unadmitted nuclear capability, according to a report by the Carnegie Endowment for International Peace, a non-profit group specializing in national security studies.The Carnegie group is merely coming to a conclusion about Pakistan that others reached long ago. The evidence of Pakistan's nuclear capability includes the country's production of highly enriched uranium, a key component of atomic weapons, and European reports of a previously clandestine effort by Pakistani officials to smuggle sophisticated nuclear components out of West Germany.

Pakistan's apparent nuclear capability is a major setback in efforts to stem the global spread of atomic weapons. But worse, it raises concerns about the possibility of a nuclear war between Pakistan and India and use of such weapons in other trouble spots.

It also creates a dilemma for the United States, because Pakistan has been a prime recipient of U.S. aid at the same time U.S. officials have been pushing that country not to develop atomic weapons.

India has responded to the Pakistan situation by quietly developing an arsenal of atomic weapons and has also worked on development of delivery systems, including medium-range rockets, the Carnegie report said. India is said to have the ingredients to build between 20 and 50 N-weapons.

As if all this weren't disquieting enough, the countries not admitting to having N-capability also happen to be the world's major trouble spots.