As US-South Korea drills draw to a close, North Korea fires ten ballistic missiles.

The presidential office of South Korea instructed its military to remain fully prepared during continuing joint drills with the United States and denounced North Korea’s firing of over ten short-range ballistic missiles on Thursday.

The launch followed North Korea’s Kim Yo Jong, the sister of Kim Jong Un, denouncing the U.S.-South Korea military exercises on Wednesday, even though U.S. President Donald Trump had ordered a significant reduction in U.S. involvement. Following North Korea’s missile launch from the Pyongyang region into the sea east of the Korean Peninsula, the presidential office called an emergency security conference that was attended by military officials and representatives from the defence ministry, according to a statement.

“The ballistic missile launch ​is a grave act that violates U.N. Security Council resolutions,” it said, calling on North Korea to immediately halt such actions.

According to South Korea’s Joint Chiefs of Staff, the missiles travelled about 300 kilometres (186 miles) toward the sea. The short-range ballistic missiles are thought to be 600 mm multiple rocket launchers, according to South Korean defence minister Ahn Gyu-back, who told MPs that Seoul has been monitoring them since they might be used close to its border with the South.

The 600 mm system, which is internationally referred to as the KN-25, has previously been said by North Korea to be capable of delivering tactical nuclear bombs.  North Korea has between 80 and 120 nuclear bombs, according to Ahn earlier in the day.

President Donald Trump ordered a significant reduction in U.S. participation in military drills between South Korea and the United States on Friday, citing his desire to resume diplomatic relations with North Korean leader Kim Jong Un. Following the cut, Kim Jong Un, the leader of North Korea, responded to Trump on Monday.

However, Kim Yo Jong, Kim’s sister, stated on Wednesday that the United States’ “hostile policy” toward North Korea has not altered and that she was not aware of any recent conversations between the presidents of the two nations.  Professor Yang Moo-jin of the University of North Korean Studies in Seoul stated that the launch seems to be intended to emphasise that Kim Yo Jong’s threat from the day before was “not mere rhetoric.”

He said the launch likely served multiple purposes, including signalling opposition to the ​South Korea-U.S. military ⁠exercises, expressing displeasure over recent discussion of North Korea’s nuclear arsenal, and warning outside powers against speculation about Pyongyang’s security affairs.

“It is a message that matters concerning North Korea’s security are for North Korea to decide,” Yang said, adding the launch could also have been used ⁠to test ​improved missile systems. During his visit to Seoul this week, Chinese Foreign Minister Wang Yi advised South Korea not to choose between Beijing and Washington, arguing that in order to reduce tensions on the Korean Peninsula, the United States should reject its “hostile” attitude toward North Korea.