The mayors of Hiroshima and Nagasaki have said in recent interviews that they hope an upcoming U.N. conference will lead countries to overcome their differences and move closer to a nuclear-free world.

Hiroshima Mayor Kazumi Matsui and Nagasaki Mayor Tomihisa Taue are both expected to deliver speeches at the conference to review the implementation of the Nuclear Non-Proliferation Treaty, which will start April 27 in New York. Both of the cities were destroyed by atomic bombs during the war.

"The rift on how to achieve a world without nuclear weapons is more like an excuse for the lack of progress," Matsui said, adding that countries should "make concessions from issues they can work on toward the goal (of nuclear abolition)."