Secretary of State John Kerry said Thursday the US atomic bombing of Hiroshima underscored the importance of the Iran nuclear deal and disarmament in general, as Japan marked the attack’s 70th anniversary.

Secretary of State John Kerry said Thursday the US atomic bombing of Hiroshima underscored the importance of the Iran nuclear deal and disarmament in general, as Japan marked the attack's 70th anniversary.

"Needless to say, it's a very, very powerful reminder of not just the impact of war in a lasting way on people, on countries, but it also underscores the importance of the agreement we reached with Iran to reduce the possibility of more nuclear weapons," Kerry said on the sidelines of a regional diplomatic gathering in Kuala Lumpur.

"And the United States and other countries are working to move to -- particularly Russia (and) the United States, with our agreement -- to reduce the number of existing nuclear weapons."

Iran and the P5+1 countries – the US, Britain, France, China and Russia plus Germany – succeeded in finalizing the text of an agreement, dubbed the Joint Comprehensive Plan of Action (JCPOA), in the Austrian capital Vienna on July 14 after 18 days of intense talks over Tehran’s nuclear program.

Under the JCPOA, limits will be put on Iran’s nuclear activities in exchange for, among other things, the removal of all economic and financial bans against the Islamic Republic.

Meanwhile, tens of thousands of people gathered Thursday in Hiroshima to commemorate the atomic bombing that killed thousands instantly and left others to die a slow death with horrible injuries.

Bells tolled as a solemn crowd observed a moment of silence at 8:15 am local time (2315 GMT), when the detonation turned the western Japanese city into an inferno.

Kerry said "our hearts go out to survivors," as he also praised the continued strong relationship between the US and Japan.