TOKYO—National Security Adviser John R. Bolton has spent the last week vacationing in Japan, according to sources close to the White House. He spent the last three days touring the "battlefields" of Hiroshima and Nagasaki, according to the sources.

Hiroshima and Nagasaki are well known as the targets of U.S. atomic bombings in 1945 that killed as many as 200,000 civilians and forced the Empire of Japan to surrender to the Allies, ending World War II. During his vacation, Bolton has sought out the handful of remaining ruins from the blasts as "reminders of just what we can do," according to one of his traveling companions, who asked not to be named.

Bolton has made no public statements during his vacation, citing a need to "relax and prepare for what's next." Mainichi Kyodatsu, a Tokyo newspaper, claimed yesterday that Bolton was overheard telling a Japanese official over dinner, "Korea is going to be nothing like Iraq. This time, the WMD are real. Yes, yes, that's a good thing!"

The longtime government official's enthusiasm for atomic weaponry is well known in Washington. In 1964, as a high school student, he campaigned for presidential candidate Senator Barry Goldwater, who advocated the use of "small" nuclear weapons as defoliants in Vietnam. Later, Bolton claimed Iraq possessed nuclear weapons in the run-up to the 2003 invasion. More recently, he argued the United States should strike North Korea's nuclear weapons program.

Bolton, who volunteered for the National Guard to avoid combat service in Vietnam, frequently enjoys battlefield tours during his vacations.