‘Denuclearisation’ started

US President Donald Trump said on Thursday North Korea was blowing up four of its big test sites and that a process of "total denuclearisation ... has already started," but officials said there was no such evidence since a landmark summit last week.

Trump said at a Cabinet meeting in the White House that "They've stopped the sending of missiles, including ballistic missiles. They're destroying their engine site. They're blowing it up. They've already blown up one of their big test sites, in fact it's actually four of their big test sites.

"And the big thing is it will be a total denuclearisation, which has already started taking place."

It was not immediately clear which North Korean test sites Trump was referring to and US officials familiar with current intelligence on North Korea's nuclear and missile test sites said there was no evidence of new moves to dismantle any sites since Trump met North Korean leader Kim Jong Un on June 12.

The officials, speaking on condition of anonymity, speculated Trump might have been referring to explosions last month that North Korea said were to destroy tunnels at the Punggye-ri nuclear test site and the dismantling of a medium-range ballistic missile test stand at Iha-ri, also in May.

There had been contact with North Korean officials since the summit, the US State Department said.

US Secretary of State Mike Pompeo "will be meeting with them and talking with them at the earliest possible date" to implement what was agreed in Singapore, spokeswoman Heather Nauert told reporters.

Asked on Wednesday if North Korea had done anything toward denuclearisation since the summit, US Defense Secretary Jim Mattis told reporters: “No, I'm not aware of that ... obviously, it's the very front end of a process.“