North Korea has fired a flurry of ballistic missiles into the Sea of Japan from its east coast, South Korea's military has claimed.

Several short-ranged weapons were reportedly shot from the northern half of the Korean peninsula in what Seoul called a potential test of weapons intended for export.

from an area near the port city of Wonsan at around 11pm GMT on Wednesday, May 7, and again shortly after midnight on Thursday.

If confirmed, the launches would mark the fourth round of ballistic missile tests to be ordered by Kim Jong Un this year, after the firing of several different missile types in January and March.

with the neighbouring nation's defence minister, Nakatani Gen, confirming Tokyo had protested to Pyongyang.

The Joint Chiefs of Staff (JCS) claimed in a statement denouncing the missile tests that its military "under the strong South Korea-US combined defence posture, is closely monitoring various North Korean activities to prevent any misjudgment (by North Korea)."

The JCS notes the missiles flew up to 500mph before landing in the water, with spokesman Lee Sung Joon determining the launches may have been to test the "performance or flight stability" of planned missile exports.

Lee did not name which country might receive the missiles, although North Korea is a Russian ally in its war in Ukraine.

Pyongyang has sent missiles, artillery and an estimated 15,000 soldiers to serve on Vladimir Putin's frontline, according to South Korea's National Intelligence Service.

The intelligence agency believes around 4,700 North Korean soldiers have been killed or injured while fighting in Ukraine.

North Korea acknowledged the deployment for the first time last month with state media quoting North Korean leader Kim Jong Un declaring he would help "annihilate and wipe out the Ukrainian neo-Nazi occupiers and liberate the Kursk area in cooperation with the Russian armed forces."

The North Korean dictator also signed a landmark mutual defence treaty alongside Russia last year following a state visit by Russian President Vladimir Putin.