Monday's exercises saw the US guided missile destroyer USS Spruance join ships, submarines and planes from the South Korean navy in waters east of the Korean Peninsula.
It was the first time U.S. and South Korean vessels have operated together in waters so close to the east coast of North Korea, a US Navy official said. The ships were armed with long-range, precision, land-attack cruise missiles, the official said.
The drills saw the US guided missile destroyer USS Spruance join ships, submarines and planes from the South Korean navy in waters east of the Korean Peninsula.
The naval show of force followed last week's flight of US Air Force B-1 bombers along the Demilitarized Zone, the closest the powerful, combat-tested heavy bombers have ever flown to the line separating North and South Korea, according to a U.S. military source.
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That flyover followed North Korea's announcement of what it claimed was a successful test of rocket engine.
Earlier this month, B-1s flew over Osan Air Base, south of the South Korean capital of Seoul, in response to North Korea's fifth test of a nuclear warhead, a test Pyongyang said showed it's ready to mount warheads on missiles.