The trip "comes as the United States builds on unprecedented cooperation with like-minded countries to strengthen regional security," Pentagon spokesman Sean Parnell said in a statement.

During the trip -- which will also take him to Hawaii and Guam -- Hegseth will participate in a ceremony to commemorate the 80th anniversary of the Battle of Iwo Jima, Parnell said.

Toward the end of World War II in 1945, Japanese and US forces engaged in a brutal, five-week combat on the tiny island around 780 miles (1,250 kilometers) south of Tokyo.

Japanese soldiers used a web of underground tunnels to fight the Americans with overwhelming firepower -- a saga that has inspired many movies and books.

Japan lost nearly all of its 21,000 soldiers on the island, while the US side lost more than 6,800 troops, with more than 19,000 wounded.

Efforts to find the remains of the war dead continue on the island, which is now off limits for civilians.