The projectile was fired into the sea east of the peninsula, Seoul's Joint Chiefs of Staff said in a statement, without immediately giving further details.

Nuclear-armed North Korea has in recent weeks tested a long-range cruise missile, a train-launched weapon and what it said was a hypersonic warhead.

Leader Kim Jong Un -- who has overseen rapid progress in its military technology, at the cost of international sanctions -- last week blamed the United States for tensions, dismissing Washington's assertions that it does not have hostile intentions.

The latest launch came as a US envoy made a new appeal for talks with Pyongyang.

"We will seek diplomacy with the DPRK to make tangible progress that increases the security of the United States and our allies," said Sung Kim, the US special representative on North Korea, following talks with his South Korean counterpart in Washington.

Kim met three times with former president Donald Trump, who boasted of stopping a war but failed to reach a comprehensive agreement on ending North Korea's nuclear programme.

President Joe Biden has promised to keep pursuing diplomacy in the quest for denuclearisation.