An American aircraft carrier heading toward the Korean Peninsula is conducting a joint exercise with Japanese naval ships in the Philippine Sea.

The U.S. Navy said in a statement that two Japanese destroyers joined the USS Carl Vinson carrier and two other U.S. warships Sunday as they continued their journey north in the western Pacific Ocean.

The Vinson canceled a scheduled visit to Australia to divert toward North Korea in a show of force, though it still conducted a curtailed training exercise with Australia before doing so.

Two Japan Maritime Self-Defense Force destroyers left Sasebo port in southern Japan on Friday to join the Vinson strike group. The U.S. group also includes a guided-missile cruiser and a guided-missile destroyer.

The exercise is designed to improve maritime response and defense capabilities.