White House wants to see 'concrete action' from N Korea on denuclearisation

The United States will continue its "maximum pressure" campaign against North Korea, the White House has said, ruling out any possibility of lifting of sanctions till Pyongyang takes "concrete action" to denuclearise.

"Certainly, the goal is denuclearisation of the peninsula. And we're going to continue the maximum pressure campaign that has been ongoing to North Korea until we see concrete actions taken toward complete and total denuclearisation," White House Press Secretary Sarah Sanders told reporters at her daily news conference on Monday.

US President Donald Trump has accepted an invitation of the North Korean leader Kim Jong-un for a summit meeting. The meeting is expected to be held later this summer. At least five non-US venues are being looked at for the summit.

Trump's pick to be the next secretary of state, CIA Director Mike Pompeo, was in Pyongyang three weeks ago to hold high level preparatory talks with the North Korean leaders.

Defence Secretary Jim Mattis, in an interaction with reporters at the Pentagon, exuded confidence that the summit meeting would yield results.

"Right now, I think there is a lot of reasons for optimism that the negotiations will be fruitful and we'll see," he said.

Sanders said North Korean leaders had agreed to denuclearise.

"Certainly in a number of conversations, including the comments I'd refer you back to. Also South Korea President Moon, who has said that North Korea has expressed a will for complete denuclearisation. That's the focus of any conversation and negotiation that the United States will have with North Korea," she added.

The Trump administration wants action from Pyongyang. Sanders said the US wouldn't make the mistake of past administrations in taking the North Koreans "simply at their word."

"We've seen some steps in the right direction, but we have a long way to go. We also have seen a major change in what has taken place in the past, by having our allies and partners in the region step up and do much more than they have in the past," she said.

China has taken a more active role in putting pressure on North Korea, Sanders said, adding that they could certainly do more.

"We hope they will, and will continue working with us. That's all at the direction and because of the relationship that the president has built with President Xi of China," she said.