"North Korea fires an unidentified projectile towards East Sea," South Korea's military said.

Seoul shared no immediate details about the launch.

It comes a week after Pyongyang fired what it said was a new hypersonic missile system aimed at deterring the country's rivals in the Pacific.

That launch was North Korea's first since US President-elect Donald Trump won the November US election and it came as US Secretary of State Antony Blinken was visiting South Korea.

US ally South Korea is a fierce rival of the North, with whom it technically remains at war.

Pyongyang's previous launch was in November, when it test-fired what it said was its most advanced and powerful solid-fuel intercontinental ballistic missile (ICBM).

In response, South Korea fired a ballistic missile into the sea in a show of force after Pyongyang's salvo of missile launches.

Washington has accused Pyongyang of receiving support from Russia in return for sending its troops to fight in Ukraine.

But neither North Korea or Russia has officially confirmed that Pyongyang's forces are fighting for Moscow.