OSAKA -- Nearly 150 people from 17 countries, including the leaders of Japanese and international peace organizations and the Arms Control Association of the United States, have called upon Japan to indefinitely postpone the Rokkasho reprocessing plant in Aomori Prefecture, warning that the project would increase the global proliferation risk of nuclear bomb materials.

Commercial reprocessing operations at Rokkasho are to begin in late spring 2007.

The appeal to stop Rokkasho was presented by the Japanese NGO Peace Boat and a representative of Physicians for Social Responsibility to Foreign Ministry delegates attending the nearly monthlong Nuclear Nonproliferation Treaty Review Conference in New York on Tuesday afternoon.

Former Nagasaki Mayor Hitoshi Motojima, musician Ryuichi Sakamoto and writer Hisae Sawachi are also among the signatories.

"Rokkasho would provide an excuse for countries such as Iran to pursue their own nuclear programs, increasing the world's supply of plutonium and highly enriched uranium. Japan should support the efforts of the International Atomic Energy Agency for a moratorium on reprocessing," said Martin Butcher, director of security programs at Physicians for Social Responsibility.