North Korea on Friday launched a barrage of cruise missiles that plunged into the sea. The launch came on the last day as the United States-South Korea concluded their military drills.

South Korea’s Joint Chiefs of Staff said that it detected the launches early Saturday morning off the North’s west coast. It added that the South Korean and US intelligence authorities analysed the key details of the launch, and boosted its surveillance posture. Seoul is demonstrating “firm military readiness” in close coordination with the US, the South Korean military said.

Earlier, on Wednesday, North Korea fired two short-range ballistic missiles into the sea in a launch that it said was meant to simulate “scorched earth” nuclear strikes on South Korea.

Seoul announced sanctions on Friday on five North Korean individuals and one company in response to Pyongyang’s launch of what it said was a space rocket last month.