South Korea and the United States have launched a joint naval exercise off the east coast of the Korean peninsula to test the combat readiness of the two allies.
Officials say the three-day drill began Monday in the East Sea near the city of Pohang. The exercise includes operating training, detecting and tracking a submarine, anti-air and anti-ship live fire training and anti-missile training.
The South Korean Navy deployed 10 vessels, while the U.S. Navy has the nuclear submarine USS San Francisco and the guided missile cruiser USS Shiloh in the maneuvers.
The drill comes as North Korea has ramped up daily threats of a nuclear test in response to expand UN sanctions imposed after its long-range rocket launch in December.