广岛原子弹爆炸70周年

More than 40,000 people have gathered in Japan's Hiroshima city for a ceremony marking 70 years since the atomic bomb was dropped on the city.

The event was held Thursday morning at Hiroshima's Peace Memorial Park, near the epicenter of the attack. In 1945, the United States dropped the world's first atomic bomb on the city, killing 140,000 people and accelerating the end of World War II.

Dignitaries also joined in the ceremony and prayed for the dead.

In a speech at the event, the Mayor of Hiroshima, Kazumi Matsui, renewed his call for US President Barack Obama and other world leaders to step up efforts toward a nuclear weapon-free world.