U.S. Ambassador to Japan Caroline Kennedy on Friday visited the Hiroshima museum showcasing devastation from the 1945 atomic bombing for the first time since she took up her current post in 2013.

"It is a solemn honor to visit this place. All who came here must feel a renewed commitment to work for peace in our troubled world," Kennedy wrote as a message on the visitor's register at the Hiroshima Peace Memorial Museum.

"We are grateful to the people of Hiroshima for their inspiring leadership and moral courage," she added, after looking at the mementos including lunch boxes and clothing of victims.

Before visiting the museum, Kennedy, accompanied by Hiroshima Mayor Kazumi Matsui, offered flowers at the cenotaph for atomic bomb victims in Hiroshima Peace Memorial Park.

"I asked the ambassador to take even one or two steps to make it a nuclear-free world as called for by President (Barack) Obama," Matsui told reporters, referring to a 2009 statement Obama gave in Prague.

The ambassador also planted dogwood trees, a symbol of friendship between Japan and the United States, on a road near the park as part of a U.S. project to present a total of 3,000 dogwood trees across Japan.

Kennedy previously visited the museum during her first visit to Japan in 1978. Although the ambassador participated last year in Hiroshima's peace memorial ceremony, held on the Aug. 6 anniversary of the atomic bombing, she did not visit the museum on that occasion.