However, asked on Wednesday if he could “put his finger on” any steps North Korea had taken to dismantle its nuclear weapons programme, Mattis told reporters at the Pentagon: “No, I’m not aware of that.”

He added: “The detailed negotiations have not begun. I wouldn’t expect that at this point.”

After the Singapore meeting Trump said that his secretary of state, Mike Pompeo, and national security adviser, John Bolton, would take part in follow-up meetings with North Korean officials this week to “go into the details” of the denuclearisation agreement the president believed he had struck with Kim.