The mayor of Hiroshima urged Japan to sign a landmark U.N. treaty banning nuclear weapons as the city yesterday marked 74 years since being targeted in the world's first atomic attack.

Mayor Kazumi Matsui raised concerns in his peace address about the rise of self-centered politics in the world and urged leaders to steadily work toward achieving a world without atomic weapons.

"Around the world today, we see self-centered nationalism in ascendance, tensions heightened by international exclusivity and rivalry, with nuclear disarmament at a standstill," Matsui said in his peace declaration.

He urged the younger generations never to dismiss the atomic bombings and the war as a mere event of history, but think of them as their own, while calling on world leaders to come to visit the cities devastated by atomic weapons to learn what happened.

Matsui used the occasion to push the Abe administration to sign the U.N. Treaty on the Prohibition of Nuclear Weapons (TPNW), approved by more than 120 nations, but rejected by the U.S. and other nuclear-armed countries.

Japan, which hosts 50,000 American troops and is protected by the U.S. nuclear umbrella, has not signed the TPNW, an omission atomic bomb survivors and pacifist groups protest as insincere.

The U.S. attack on Hiroshima on Aug. 6, 1945, killed 140,000 people. The bomb dropped three days later on Nagasaki killed another 70,000 before Japan's surrender ended World War II.