US President Donald Trump issued a fresh threat against North Korea, saying it should expect 'big, big trouble' if anything happened to Guam. Photo: BBC News

Mr Trump and North Korea have been exchanging hostile rhetoric, with the US president threatening to rain "fire and fury" on the North.

But China, North Korea's only major ally, has been urging restraint.

A White House statement said the US and China agreed North Korea must stop "provocative and escalatory behaviour".

A statement by North Korea's official KCNA news agency issued on Saturday said the Trump administration "had better talk and act properly," if it did not want "the American empire to meet its tragic doom".

Long-standing tensions over North Korea's nuclear programme worsened when it tested two intercontinental ballistic missiles in July.

The regime was also angered by last week's UN decision to increase economic sanctions against it.

According to Chinese state media, Mr Xi told Mr Trump in a phone call that "all relevant parties" should stop "words and deeds" that would exacerbate the situation.

Mr Xi also stressed China and the US shared "common interests" over denuclearisation and maintaining peace on the Korean peninsula.

A White House statement on the phone call did not mention the apparent plea to the US president.

It stressed the two men enjoyed a close relationship, which would "hopefully lead to a peaceful resolution of the North Korea problem".

President Trump has previously chided China for not reining in North Korea, saying it could do "a lot more".

North Korea has announced plans to fire missiles near the Pacific territory of Guam, but there is no indication an attack is imminent.

On Friday, Mr Trump issued a fresh threat against North Korea, saying it should expect "big, big trouble" if anything happened to Guam.

But he added: "Hopefully, it will all work out. Nobody loves a peaceful solution better than President Trump, that I can tell you."