Britain welcomes US-North Korea talks, says UK PM Theresa May's spokesman

Britain will keep up pressure on North Korea even as it welcomes progress towards talks between its leader Kim Jong Un and U.S. President Donald Trump, a spokesman for British Prime Minister Theresa May said on Friday.

Trump said he was prepared to meet North Korea's Kim in what would be the first face-to-face encounter between the two countries' leaders and could mark a breakthrough in the standoff over the North's nuclear weapons.

"We have always been clear that we want Kim Jong Un to change path and put the welfare of his people ahead of the illegal pursuit of nuclear weapons," May's spokesman said.

"We will continue to work closely with the US, South Korea and the international community to ensure that pressure on North Korea continues and sanctions are strictly enforced until Kim Jong Un matches his words with concrete actions."

Earlier on Friday, US Secretary of State Rex Tillerson said talks between US President Donald Trump and North Korean leader Kim Jong Un will take some weeks to arrange.

Trump said on Thursday he was prepared to meet Kim in what would be the first face-to-face encounter between any leaders of the two countries. It potentially marks a major breakthrough in easing tensions over Pyongyang's nuclear weapons programme.

"President Trump has said for some time that he was open to talks and he would willingly meet with Kim when conditions were right," Tillerson said. "And I think in the president's judgment that time has arrived now."

The decision was made by the president himself, Tillerson said during a visit to Djibouti.

"Now it's a question of agreeing on the timing of the first meeting between the two of them, and that will take some weeks before we get all that worked out."

Trump has derided Kim as a "maniac", referred to him as "little rocket man", and threatened in a speech to the United Nations last year to "totally destroy" North Korea if it attacked the United States or one of its allies.

Kim responded by calling the US president a "mentally deranged US dotard".

Trump's aides have been wary of North Korea's diplomatic overtures because of its history of reneging on international commitments and the failure of efforts on disarmament by previous US administrations.

Some US officials and experts worry North Korea could buy time to build up and refine its nuclear arsenal if it drags out talks with Washington.

Kim has committed to denuclearisation and to suspending nuclear and missile tests, South Korea's National Security Office head Chung Eui-yong said on Thursday after briefing Trump on a meeting South Korean officials held with Kim earlier this week.