An international forum on nuclear nonproliferation and disarmament began Friday in Tokyo to discuss ways to step up measures to strengthen the global regime to prevent nuclear arms races.

Nobuo Matsunaga, vice chairman of the Japan Institute of International Affairs, a Tokyo-based private think tank, asked some 20 experts participating from 17 countries to be "constructive and flexible" in finalizing policy recommendations in a report.

Matsunaga cohosts the three-day Tokyo Forum with Yasushi Akashi, former head of the Hiroshima Peace Institute and a former undersecretary general of the United Nations.

The international regime for nuclear nonproliferation has been put to a severe test since May 1998, when India and Pakistan launched a new round of nuclear weapons tests.