F/A-18F launches from the USS Rossevelt
An F/A-18F Super Hornet launches from the flight deck of the USS Theodore Roosevelt. Navy photo

The San Diego-based aircraft carrier USS Theodore Roosevelt joined warships from South Korea and Japan in naval exercises to ensure readiness against nuclear and missile threats from North Korea, Seoul’s navy announced on Friday.

North Korea has been accelerating weapons development, testing solid-fuel hypersonic missiles last week, and leader Kim Jong Un said on Wednesday now was the time to be more prepared for war than ever, citing an unstable geopolitical situation.

“The participating forces conducted anti-submarine warfare drills to improve their responses to North Korean underwater threats including from submarines and submarine-launched ballistic missiles,” the South Korea’s navy said in a statement.

The two-day drill held in international waters between South Korea and Japan beginning Thursday brought together the Roosevelt and San Diego-based guided-missile destroyer USS Russell along with other U.S. and allied Warships.

The training, aimed to step up their combined capability to respond to North Korea’s threats, follows a multi-year joint exercise plan set up after last year’s three-way summit, the South Korean navy said.

The three navies also practiced maritime interdiction exercises designed to block North Korea’s illegal transport of weapons of mass destruction, and search and rescue training to help ships in distress.

In Washington, South Korean and U.S. defense officials held annual defense talks on Thursday, reaffirming plans for tabletop exercises simulating North Korea’s use of a nuclear weapon in upcoming summer drills, Seoul’s defense ministry added.

At the Camp David summit last August, leaders of the three countries agreed to stage annual, multi-domain exercises, share real-time information on North Korean missile launches and launch a hotline for crisis communications.