S Korea urges 'parallel' talks, sanctions

South Korea's new president launched international efforts to defuse tension over North Korea's weapons development on Thursday, urging both dialogue and sanctions while also aiming to ease China's anger about a US anti-missile system.

Moon Jae-in, a liberal former human rights lawyer, was sworn in on Wednesday and said in his first speech as president he would immediately address security tensions that have raised fears of war on the Korean Peninsula.

Moon first spoke to Chinese President Xi Jinping and later to Japanese Prime Minister Shinzo Abe. The conversations were dominated by how to respond to North Korea's rapidly developing nuclear and ballistic missile programmes, which are in violation of UN Security Council resolutions.

Moon has taken a more conciliatory line with North Korea than his conservative predecessors and advocates engagement. He has said he would be prepared to go to Pyongyang "if the conditions are right."

Moon's advocacy of engagement with North Korea contrasts with the approach of the United States, South Korea's main ally, which is seeking to step up pressure on Pyongyang through further isolation and sanctions.

On Thursday, the US director of National Intelligence, Dan Coats, told the Senate Intelligence Committee that North Korea posed "a very significant, potentially existential threat to the United States that has to be addressed."

Regional experts have believed for months that North Korea is preparing for its sixth nuclear test. It has also been working to develop a nuclear-tipped missile capable of reaching the United States, presenting Trump with perhaps his most pressing security issue.

Trump told Reuters in an interview last month major conflict with North Korea was possible but he would prefer a diplomatic outcome.

North Korea says it needs its weapons to defend itself against the United States which it says has pushed the region to the brink of nuclear war.