Bells tolled and thousands bowed their heads in prayer in Hiroshima on Thursday at ceremonies that marked the 70th anniversary of the world's first atomic bombing. [Photo/CFP]

Japan's pacifist constitution bans the country from using force outside Japan, but the security-related bills being pushed by the Abe administration in the Diet would allow Japan to fight wars.

The bills are considered as a violation of the constitution by over 90 percent of the country's experts on legislation.

After the ceremony, a group formed by victims of the atomic bombing expressed to Abe their hope that the government could retract the security bills but got negative answer from the prime minister.

To accelerate Japan's surrender in the WWII, the US forces dropped two atomic bombs on Hiroshima and Nagasaki respectively on Aug. 6 and Aug. 9, 1945. Japan surrendered to the Allied Forces on Aug. 15, 1945, bringing an end to the war.