North Korea launched several suspected short-range ballistic missiles from its east coast, according to South Korea’s military on Thursday, possibly to evaluate the performance and stability of different missiles meant for export.

The projectiles were fired from Wonsan, an eastern coastal city in North Korea, at approximately 8:10 a.m. (2310 GMT Wednesday) and traveled up to 497 miles, falling into the sea, as reported by the military.

South Korea is closely communicating with the US and Japan to share information about the launch, it added.

The foreign ministry said the three countries’ nuclear envoys consulted by telephone and condemned it as a violation of UN sanctions.

Lee Sung-jun, a spokesperson for South Korea’s Joint Chiefs of Staff, did not provide specifics on the number of missiles identified or their properties but informed reporters that the launch might have been conducted to test missiles slated for export.

A North Korea analyst at the Korea Institute for National Unification, Hong Min, said they were likely two types of short-range ballistic missiles that had been supplied to Russia which used them to strike Ukraine.

“There is considerable amount of field data of these two missiles collected, and it’s possible additional testing was needed to improve issues reported from the battlefield such as durability and precision,” Hong said.

The Japanese government also said it detected a launch of a ballistic missile by North Korea, which may have flown on an irregular trajectory.

The nuclear-armed North’s ballistic missile programme is banned by United Nations Security Council resolutions, but in recent years Pyongyang has forged ahead in developing missiles of all ranges.

In March, North Korea fired multiple ballistic missiles, while blaming the South Korean and US militaries for conducting drills it calls dangerous and provocative.

North Korea has exported short-range ballistic missiles, among other weapons, to Russia for use in the war in Ukraine, according to US and allied intelligence agencies as well as independent researchers.

Pyongyang and Moscow have denied the weapons trade, although North Korean troops have been deployed to fight on the frontlines in Russia’s Kursk region.