North Korea fired two suspected short-range ballistic missiles (SRBM) on Monday from an airport in its capital city of Pyongyang, South Korea's military reported, the fourth test this month to demonstrate its expanding missile arsenal.
Japan also reported the launch, with chief cabinet secretary Hirokazu Matsuno condemning it as a threat to peace and security.
In less than two weeks, nuclear-armed North Korea has conducted three other missile tests, an unusually rapid series of launches. Two of them involved single "hypersonic missiles" capable of high speed and manoeuvring after launch, while a test on Friday involved a pair of short-range ballistic missiles (SRBMs) fired from train cars.
Monday's launch appeared to involved two SRBMs fired east from Sunan Airfield in Pyongyang, South Korea's Joint Chiefs of Staff said in a statement.
North Korea used the airport to test fire the Hwasong-12 intermediate-range ballistic missile (IRBM) in 2017.
Japanese Defence Minister Nobuo Kishi said the missiles appeared to have travelled about 300 km and landed in the ocean near North Korea's east coast.
"It is self-evident that the aim of North Korea’s frequent missile launches is to improve their missile technology," he told reporters.
"The repeated launching of North Korea’s ballistic missiles is a grave problem for the international community, including Japan," Kishi added, noting that the launches were a violation of UN Security Council resolutions that ban North Korea from all ballistic missile development.
The pace of testing and variety of launch sites suggests that North Korea has enough missiles to feel comfortable expending them on tests, training, and demonstrations, and helps reinforce its deterrent credibility by emphasizing the volume of its missile force, said Mason Richey, a professor at Hankuk University of Foreign Studies in Seoul.
North Korea has not tested its longest-range intercontinental ballistic missiles (ICBMs) or nuclear weapons since 2017, but after denuclearisation talks stalled in 2019, it began unveiling and testing a range of new SRBM designs.
Many of the latest SRBMs, including the hypersonic missiles, appear designed to evade missile defences. North Korea has also vowed to pursue tactical nuclear weapons, which could allow it to deploy nuclear warheads on SRBMs.
"Every tactical missile launch flaunts how little sanctions have constrained the Kim regime, and how the U.S. ... has failed to make North Korea pay a sufficient cost for short-range missile programme development," Richey said.