Nagasaki marked the 76th anniversary Monday of the U.S. atomic bombing of the city in World War II, with its mayor urging the Japanese government to take a more active role in realizing a world free of nuclear weapons.

At the annual memorial ceremony, Mayor Tomihisa Taue urged the government to sign and ratify a U.N. treaty banning nuclear weapons and join as an observer in its first meeting of state parties to the treaty, which came into effect in January, and explore building a nuclear-weapon-free zone in Northeast Asia.

After a moment of silence was observed at 11:02 a.m., the exact time of the bombing on Aug. 9, 1945, Taue praised the Treaty on the Prohibition of Nuclear Weapons as a "new horizon" for nuclear disarmament but also expressed concern about the growing danger presented by an ongoing nuclear arms race.