John Kerry will not offer an apology for the United States' use of the atomic bomb against Japan when he becomes the first U.S. secretary of state to visit the Hiroshima Peace Memorial Museum on Monday, a senior U.S. official said.

Kerry is visiting the city, which was obliterated by a U.S. atomic bomb on Aug. 6, 1945, to attend gathering of foreign ministers from the Group of Seven (G7) advanced economies that Japan opened on Sunday with a call to end nuclear weapons.

The U.S. diplomat is to join his counterparts from Britain, Canada, France, Germany, Italy and Japan on Monday to tour the city's atomic bomb museum and to lay flowers at a cenotaph for its victims, becoming the first in his post to do so.

"If you are asking whether the secretary of state came to Hiroshima to apologize, the answer is no," a senior U.S. official told reporters late on Sunday.

"If you are asking whether the secretary and I think all Americans and all Japanese are filled with sorrow at the tragedies that befell so many of our countrymen, the answer is yes," the official, who spoke on condition of anonymity, added.