The U.S. nuclear-powered aircraft carrier Ronald Reagan left its home base in Yokosuka, near Tokyo, on Tuesday on a long-term patrol in the surrounding ocean area, the U.S. Navy said.

The departure of the aircraft carrier, a symbol of U.S. military force in the sea near the Korean Peninsula, comes as the United States and North Korea negotiate over a plan to hold a first-ever summit between the two countries in Singapore next month.

The Ronald Reagan engaged in a joint military drill last November with two other nuclear-powered flattops in the Sea of Japan, in a show of force amid Pyongyang's growing nuclear and missile threats.

This time it will hold takeoff and landing exercises for carrier-based aircraft stationed at the Marine Corps air base in Iwakuni in the western Japan prefecture of Yamaguchi, in the Pacific off Kyushu.

The Ronald Reagan had completed a week-long trial voyage in mid-May after returning to its home base from a long trip in December and undergoing inspection and maintenance.