North Korea launched one short-range ballistic missile toward the East Sea on Sunday morning, according to the South Korean Joint Chiefs of Staff (JCS).

It’s Pyongyang’s first known missile test since mid-August, when it launched cruise missiles from the west coast, and comes just days after the aircraft carrier USS Ronald Reagan arrived in South Korea’s southern port city of Busan in what observers have called a show of force against the North.

The JCS said the test represents “a grave provocation which threatens peace and stability on the Korean Peninsula and indeed the entire international community.”

The South Korean military said the North fired a single short-range ballistic missile (SRBM) from Thaechon County in North Phyongan Province at 6:53 a.m. KST while the Japan Coast Guard reported that the missile splashed down in the ocean less than 18 minutes later, before 7:11 a.m.

The missile reached a top speed of Mach 5 over a distance of 373 miles (600 km), with a maximum altitude of 37 miles (60 km), according to a JCS statement released later in the morning.

The statement added that Seoul and Washington will counter “North Korean threats and provocations” through joint naval exercises planned for Sept. 26 to 29, and that JCS chief Kim Seung-kyum discussed the missile test Sunday morning with Gen. Paul LaCamera, commander of U.S. Forces Korea (USFK) and U.S.-ROK Combined Forces Command (CFC). 

The South Korean National Security Council (NSC) also condemned the test as a “provocation” at an emergency meeting Sunday and informed President Yoon Suk-yeol about the situation, though he did not attend the meeting.  

Ankit Panda, a senior fellow at the Carnegie Endowment for International Peace and NK Pro contributor, told NK News the flight distance is roughly the same as the distance between Thaechon and Busan, sending a “straightforward” signal and “reminder that they can make the alliance’s life very difficult in a conflict by putting a nuclear weapon on Busan if they need to.”

“[The U.S.] signaled resolve and assurance for South Korea with the [aircraft carrier] visit and they sent their own signal in return,” he added. “It’s an old pattern.”

If North Korea releases details on Sunday’s test, it is likely to do so on Monday morning at the earliest. However, DPRK state media has not offered dedicated reports on its last six consecutive missile test events. 

The leader’s sister, Kim Yo Jong, publicly acknowledged the cruise missile test briefly in August but only to mock South Korean authorities for what she said was their incorrect identification of the test’s location.

Xu Tianran, an analyst with Open Nuclear Network, told NK News the flight data released for the missile tested Sunday most resembles that of a KN-23 SRBM, but that DPRK state media would likely need to release photos in order to confirm the type. Multiple analysts pointed out that it is odd for North Korea to test only a single solid-fueled SRBM, as they are usually tested in pairs.

Meanwhile, an NSC deputy director also warned ROK President Yoon on Friday about the possibility North Korea would test a submarine-launched ballistic missile (SLBM) in the coming days. 

NK News also detected signs of a crane being moved over the North’s 8.24 “Yongung” Gorae-class submarine in Sinpho on the east coast in satellite imagery taken Sept. 22 — activity seen in the past related to loading a missile into a vertical canister in the submarine or carrying out repairs after a launch. 

A medium-resolution image of the Sinpho South Shipyard taken on Sept. 22 (left) shows what appears to be a crane with its boom extended over the submarine under a canopy (circled in yellow). The possible crane did not appear in another image taken on Sept. 24 (right). | Images: Planet Labs PBH, edited by NK News

Edited by Arius Derr

Updated on Sept. 25 at 10:36 a.m. KST with details from JCS about the missile’s flight data, at 11:36 a.m. with details about an NSC emergency meeting, and on Sept. 26 at 6:30 a.m. with additional expert comments.