South Korea and the U.S. kicked off a four-day joint maritime exercise in the East Sea on Monday, mobilizing some 20 warships including the nuclear-powered aircraft carrier USS Ronald Reagan and about 110 warplanes.
This is the first time the drill has been conducted since November 2017. North Korea fired a new ballistic missile into the East Sea the previous day. The two countries are staging the drill from Monday until Thursday in a show of force against North Korean provocations and improve their combat readiness.
The U.S. mobilized the 6,000-ton submarine USS Annapolis for training in preparation for North Korean attacks with submarine-launched ballistic missiles.
The North is building a new submarine in Sinpo, South Hamgyong Province that is expected to be capable of carrying powerful missiles that are hard to detect early.
It has been developing submarine-launched ballistic missiles that will make it possible to launch clandestine attacks by avoiding South Korea and the U.S. defenses.
Meanwhile, China is conducting naval drills in the West Sea. The China Maritime Safety Administration said military missions are scheduled in the northern West Sea from Sept. 25 until Oct. 2.