Donald Trump has said that North Korea should be "very, very nervous" if it does anything to the US, in the latest salvo in the war of words between the countries.

In the aftermath of comments by Pyongyang that it was coming up with plans to fire four missiles near the US island of Guam, Trump said the regime would be in trouble "like few nations have ever been" if they do not "get their act together".

Trump also said his "fire and fury" comments were possibly not tough enough.

"If North Korea does anything or is even thinking about an attack on anybody that we love or represent, or our allies or us, they should be very, very nervous," the President said.

He also said that the US would look at negotiating with the rogue nation while he was at his golf club in New Jersey but issued a call to China to pressure Pyongyang.

"I have great respect for China and Russia and what they did on sanctions... I think China can do a lot more, yes, and I think China will do a lot more."

He added: "The people of our country are safe, our allies are safe, and I will tell you this: North Korea better get their act together, or they're gonna be in trouble like few nations have ever been in trouble in this world."

North Korea has said that a decision would be made within days over its intentions to fire missiles at Guam. It has tested two intercontinental ballistic missiles (ICBM) and US military experts say that Pyongyang has managed to miniaturise nuclear warheads for the missiles.

donald trump
The Internet was left horrified after Trump sternly warned North Korea that any threats to the US would be met with "fire and fury." Reuters/Jonathan Ernst