Hiroshima Mayor Kazumi Matsui and Setsuko Thurlow, an atomic bombing survivor and peace advocate, on Monday urged new Prime Minister Fumio Kishida to take an active role in realizing a world free of nuclear weapons.

Matsui expressed hope that Kishida, who hails from a political family in Hiroshima, will take the initiative by making use of his experience as a foreign minister. The mayor urged the government to participate as an observer in a conference next year of the parties of the U.N. treaty to ban nuclear arms.

Japan — the only country to have suffered atomic bombings, in Hiroshima and Nagasaki in 1945 — has refused to join the treaty along with the world's nuclear weapons states, as it relies on the U.S. nuclear umbrella.