(CNN) Seoul – The drill Monday involved howitzers, mortars and attack helicopters, South Korean news agency Yonhap reported. It took place on islands off the west coast of the Korean peninsula where tensions have flared in the past.
Seoul notified the North on Sunday of the drill, a regular live-fire exercise that lasts an hour. About 1,000 island residents were moved to safe areas during the drill, Yonhap reported, citing military officials.