Xi Jinping and Donald Trump spoke on the phone, with the Chinese president calling for restraint as international concern mounted about the US president's brinksmanship on North Korea.

Mr Trump continued to escalate his rhetoric, tweeting that the US military was "locked and loaded".

"Military solutions are now fully in place, locked and loaded, should North Korea act unwisely," he wrote.

Asked about his comments by reporters, Trump, referring to Kim, said: "If he utters one threat ... or if he does anything with respect to Guam or any place else that's an American territory or an American ally, he will truly regret it, and he will regret it fast."