Japan's Prime Minster and Hiroshima mayor together with at least 50 thousand people including representatives from different nations gathered together on Thursday to mark the 64th anniversary of the world's first atomic bomb attack.

Japan will continue to uphold its three non-nuclear principles and lead the international community toward the abolishment of nuclear weapons and lasting peace, said Prime Minister Taro Aso at Thursday's ceremony.

The three principles state that Japan will not make, own or harbor nuclear weapons.

Hiroshima's mayor Tadakoshi Akiba welcomed U.S. President Barack Obama's call to abolish nuclear weapons in the world.

 We refer to ourselves, the great global majority, as the 'Obamajority,' and we call on the rest of the world to join forces with us to eliminate all nuclear weapons by 2020, Akiba said at the ceremony.

In April, Obama said that the United States — the only nation that has deployed atomic bombs in combat — has a moral responsibility to act and declared his goal to get rid of nuclear weapons in the world.

Together, we can abolish nuclear weapons. Yes, we can, Akiba said.

Later in the day, Aso signed an agreement with a group of atomic bomb survivors who had been seeking recognition and expanded health benefits from the government.

A similar ceremony will be held in Nagasaki on Sunday August 9.

Hiroshima was attacked on August 6, 1945 and instantly flattened. An estimated 1,40,000 people were killed or died within months when the American B-29 bomber Enola Gay dropped its atomic bomb during World War II.

Three days after that attack on Hiroshima, the U.S. dropped a plutonium bomb on the city of Nagasaki, killing about 80,000 people.

Japan surrendered on August 15, ending World War II. A total of about 260,000 victims of the attack are officially recognized by the government, including those that have died of related injuries or sickness in decades.