Participating U.S. forces included the Arleigh-Burke-class guided-missile destroyer USS William P. Lawrence and a maritime patrol aircraft, according to South Korean naval officials. South Korea contributed roughly 10 aircraft and 10 warships, including the destroyer ROKS Yulgok Yi I.

The top military officers of South Korea and the US vowed to further strengthen the allies' trilateral security cooperation with Japan during their first video talks earlier this week, the

North Korea launched a series of short-range ballistic missiles during a nuclear counterstrike drill overseen by leader Kim Jong Un, in what state media said was a response to recent nuclear exercises by the United States and South Korea.

North Korea is in its "strongest strategic position in decades," the U.S. Defense Intelligence Agency said in a new assessment.