Japan has given in to India's demand that it be allowed to reprocess spent nuclear fuel from Japanese-made reactors, negotiation sources said, marking a major shift in Japan's stance against proliferation.

India, a nuclear power that conducted its first weapons test in 1974 using reprocessed plutonium, has not joined the Nuclear Non-Proliferation Treaty. Japan has been seeking measures to guarantee India will not divert extracted plutonium — which could be used to build nuclear weapons — for military use, but no agreement has been reached on the issue, the sources said Thursday.

This is the first time Tokyo has allowed a country using Japanese reactors to conduct fuel reprocessing. Since the Fukushima meltdowns in 2011, Japan has concluded nuclear equipment supply agreements with six countries, including Jordan, Russia, Turkey and Vietnam. But not one had been allowed to reprocess spent fuel generated by the reactors.