Japan's Defense Ministry says the Maritime Self-Defense Force and the US Navy are holding joint military drills in waters off Japan, aimed at strengthening the deterrence capabilities as a time when North Korea is repeatedly carrying out ballistic missile launches.

The ministry says the drills involving one MSDF destroyer and four US Navy vessels, including the nuclear-powered aircraft carrier USS Ronald Reagan, started on October 1.

The aircraft carrier was redeployed in the Sea of Japan, following its deployment in the waters in late September. It carried out two-day maneuvering drills with South Korean forces until Saturday.

North Korea's Ministry of National Defence criticized the drills in a statement on Saturday.

Japan's Defense Ministry says it decided to disclose the drills while they are still ongoing, after considering various elements comprehensively and coordinating with the United States.

It says the drills aim to strengthen the deterrence capabilities of the bilateral alliance at a time when the security situation surrounding Japan is becoming increasingly severe.