Japan’s defense minister, Shinjiro Koizumi, again called for an open and frank discussion on nuclear weapons in the country, at a symposium in Tokyo, according to the Russian state agency TASS, which cites Kyodo News.

“We must create conditions in which the security measures necessary for Japan can be discussed openly and frankly,” he said. The statement comes amid the review of the national security strategy, which also touches on Japan’s three non-nuclear principles: not to possess, produce or introduce nuclear weapons into its territory. Koizumi also once again left the door open to potentially equipping the country’s navy with nuclear submarines.