It comes after North Korea fired a submarine-launched ballistic missile (SLBM) on Tuesday, prompting an emergency meeting of the UN Security Council.

US special representative on North Korea Sung Kim met his southern counterpart Noh Kyu-duk after a meeting with their Japanese counterpart in Washington.

He labelled Tuesday's launch a "provocation", and urged Pyongyang to stop "concerning and counterproductive" missile tests.

"We hope the DPRK will respond positively to our outreach," Kim told reporters in Seoul, using the acronyms of North Korea's official same.

Tuesday's launch was the latest in a series of recent weapons tests by the country, including a long-range cruise missile, a train-launched weapon, and what it said was a hypersonic warhead.

Earlier this month, North Korean leader Kim Jong Un blamed the United States for sanctions, dismissing Washington's assertions that it does not have hostile intentions.

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

President Joe Biden has promised to keep seeking diplomacy but with a more low-key approach.