China urges talks with North Korea

The crisis over North Korea's weapons programs must be resolved through talks, not war, Chinese President Xi Jinping said, while UN Secretary-General Antonio Guterres warned of the danger of "sleepwalking" into conflict.

Xi made his comments to visiting South Korean President Moon Jae-in after US Secretary of State Rex Tillerson offered on Tuesday to begin direct talks with North Korea without pre-conditions.

But the White House said on Wednesday that no negotiations could be held until North Korea improved its behaviour.

Russian President Vladimir Putin said Tillerson's offer of direct contacts with North Korea was "a very good signal" while warning that any US strike on the country would have catastrophic consequences.

Putin and US President Donald Trump discussed North Korea during a phone call, the White House and Kremlin said in separate statements. The two leaders talked about "working together to resolve the very dangerous situation," the White House said on Thursday.

North Korea tested its most advanced intercontinental ballistic missile on November 29, which it said could put all of the United States within range, in defiance of international pressure and UN sanctions.

Meeting in Beijing's Great Hall of the People, Xi told Moon the goal of denuclearising the Korean peninsula must be stuck to, and war and chaos cannot be allowed, Chinese state media said.

Also on Friday, Japan announced it will impose additional sanctions on North Korea following repeated threats by Pyongyang's missiles and nuclear programme.

Chief Cabinet Secretary Yoshihide Suga told a news conference that Japan would freeze assets of 19 more North Korean institutions.