Donald Trump brags of having a 'bigger button' than Kim Jong-un

US President Donald Trump has bragged about the size of the button he can used to deploy nuclear weapons.

Mr Trump tweeted he has a "bigger button" than North Korea's Supreme Leader Kim Jong-un, making light of the serious threat of nuclear attacks.

It comes in response to Mr Kim saying "a nuclear button is always on my desk" during a speech on New Year's Day.

"North Korean Leader Kim Jong Un just stated that the 'Nuclear Button is on his desk at all times.' Will someone from his depleted and food starved regime please inform him that I too have a Nuclear Button, but it is a much bigger & more powerful one than his, and my Button works!" Mr Trump said.

During Mr Kim's speech, he said the United States in within range of North Korea's nuclear weapons, and that is "a reality, not a threat".

"This year we should focus on mass producing nuclear warheads and ballistic missiles for operational deployment. These weapons will be used only if our security is threatened."