Kim Jong-un calls Trump 'mentally deranged' in response to his U.N. threat to 'destroy' North Korea
Undated picture released from North Korea's official Korean Central News Agency on Jan. 10, 2016 shows North Korean leader Kim Jong-Un delivering a speech at the Ministry of the People's Armed Forces in Pyongyang (AFP)

North Korea's leader Kim Jong-un said American President Donald Trump has exhibited "mentally deranged behavior," NBC Nightly News tweeted.

The American president gave an "unprecedented rude nonsense one has never heard from any of his predecessors" in his speech threatening to "destroy" North Korea, Kim reportedly said to the country's state media service.

Kim said Trump "insulted me and my country in front of the eyes of the world" and "will face results beyond his expectation."