China's Liaoning aircraft carrier strike group conducted exercises east of the Philippines, as Tokyo tracked the flotilla from May 26 through Friday

The Maritime Self-Defense Force tracked China's Liaoning aircraft carrier and accompanying vessels in waters east of the Philippines' Luzon island from May 26 through Friday, according to a statement from Japan's Defense Ministry Joint Staff announced late Monday.

The flotilla was observed heading southeast from an area off Luzon on Friday; the current whereabouts of the warships was not immediately clear.

China's military activity prompted criticism from Beijing toward Japan over its defense buildup and growing security ties with the Philippines.