The mayors of the two cities destroyed by atomic bombs in the final days of World War II hope U.S. President Barack Obama's visit to Hiroshima on Friday will be a "new step" toward realizing a world free of nuclear weapons.

In separate interviews, Hiroshima Mayor Kazumi Matsui described the first trip by a sitting U.S. leader to the city as "politically a very crucial phase," while Nagasaki Mayor Tomihisa Taue said he expects other world leaders to follow suit after Obama's visit.

The Hiroshima and Nagasaki mayors have repeatedly asked the U.S. president — who was awarded the Nobel Peace Prize in 2009 after his landmark speech calling for a world without nuclear weapons — to visit their cities.