Image copyright Reuters Image caption North Korea's ambassador to the UN, Ja Song Nam, said Pyongyang posed no threat as long as its interests were not infringed upon

US Secretary of State Rex Tillerson said North Korea must "earn its way back to the table" for negotiations between the two countries to restart.

Mr Tillerson said Pyongyang had to carry out a "sustained cessation" of weapons testing before any talks.

It is a U-turn from comments made earlier this week, when Mr Tillerson said the US was "ready to talk any time time North Korea would like to talk".

That remark was swiftly contradicted by the White House.

North Korea has carried out repeated nuclear and ballistic missile tests this year, in defiance of global condemnation and increasingly heavy international sanctions.

Earlier this week Mr Tillerson said: "Let's just meet and let's talk about the weather if you want and talk about whether it's going to be a square table or a round table if that's what you're excited about.

"Then we can begin to lay out a map, a road map, of what we might be willing to work towards."

Image copyright Reuters Image caption There are reports that Mr Tillerson had planned to repeat his offer of talks without preconditions

But his remarks, welcomed by China and Russia, were promptly greeted with a rebuttal from the White House and a reiteration that North Korea must admit to abandoning its nuclear weapons before talks resume.

Within just a few hours press secretary Sarah Saunders released a statement to reporters saying Mr Trump's views "have not changed".

"North Korea is acting in an unsafe way not only toward Japan, China, and South Korea, but the entire world," she said.

On Friday, Mr Tillerson also urged Russia and China to put more pressure on Pyongyang by taking action beyond mere compliance with UN Security Council resolutions. Both countries rejected this.

He told the UN Security Council that diplomatic options remained open, but that the US would not bow to North Korean conditions for negotiations.

"We do not accept any relaxing of the sanctions regime as a precondition of talks," he said.

"We do not accept the resumption of humanitarian assistance as a precondition of talks. So we are not going to accept preconditions for these talks."

Also on Friday at the Security Council: