Foreign Minister Fumio Kishida called on nuclear-weapon states Monday to improve the transparency of information regarding their atomic arsenals, apparently wary of China's buildup of its nuclear forces.

At the start of U.N. conference in New York to review the operation of the Nuclear Nonproliferation Treaty, Kishida also reiterated his hope that political leaders from around the world will visit the Japanese cities devastated by the U.S. atomic bombings at the end of World War II to witness the reality of the attacks.

Kishida took part in the NPT review conference as the first Japanese foreign minister to do so in 10 years. The meeting has been held every five years since the treaty went into effect in 1970.