United States President Donald Trump on Tuesday taunted North Korea leader Kim Jong-un for his claims of having a nuclear button on his desk, saying his button was “much bigger and more powerful”.

“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!” Trump said.

The president’s tweet was in response to Kim’s New Year’s Day speech, in which he had said: “The nuclear button is always on my table. This is not blackmail but reality.”

Trump’s tweet is the latest in a long war of words between the two leaders after North Korea conducted a string of nuclear tests in 2017. The US president had called Kim “Little Rocket Man” and “madman”, while the North Korean leader had called Trump a “dotard”.

North Korea was condemned globally for conducting its sixth and most powerful nuclear test – which it claimed was a hydrogen bomb – in September. In December 2017, the United Nations Security Council imposed new sanctions on North Korea for its ballistic missile programmes.