US Secretary of State John Kerry said Monday he was "deeply moved" by his visit earlier in the day to the Hiroshima atomic bomb memorial in the Japanese city.

"I want to express on a personal level how deeply honoured I am, how deeply moved I am" to be the first US secretary of state to visit the Hiroshima memorial, he told reporters. 

Kerry said the museum was "extraordinary" and called it a "gut-wrenching display that tugs at all your sensibilities as a human being".