South Korea's defense ministry says it is starting two-day drills with Japan and the United States on Monday in the seas south of the Korean Peninsula.

Ministry officials say its naval forces are joining Japan's Maritime Self-Defense Force and the US Navy in the exercises in the international waters off Jeju Island. Vessels taking part include a US nuclear-powered aircraft carrier, the USS Nimitz.

The officials say the trilateral drill will check procedures for dealing with submarines for the first time since last September.

The ministry says the exercise is designed to enhance the response capabilities of South Korea, the US and Japan against North Korea's underwater threats, including submarine-launched ballistic missiles.

The officials say the three nations are also resuming joint search-and-rescue drills for the first time since 2016. They say that's part of moves to normalize trilateral security cooperation.

The joint exercises off Jeju by the US and South Korean forces on March 27 were shown to the media. They included aircraft taking off and landing on the USS Nimitz.

The ongoing exercise apparently underscores efforts to bolster the three-nation security cooperation.