North Korea has severed diplomatic ties with Malaysia, which have deteriorated sharply since the shocking murder of Kim Jong-un's half-brother at the airport four years ago, AFP reported.

The North Korean MFA said it was responding to Malaysia's extradition of a North Korean citizen to the United States, a move it called an unforgivable crime committed as a result of blind obedience to US pressure.

Malaysia was one of the country's few allies until North Korean leader Kim Jong Nam's half-brother was killed by a banned nerve agent while awaiting departure.

Ties deteriorated sharply but began to get back on track when Malaysia announced the reopening of its embassy in Pyongyang.

The North Korean Foreign Ministry announced today a complete severance of diplomatic relations with Malaysia, stating that the extradited citizen was involved in legitimate trade activities in Singapore.

On March 9, a North Korean citizen lost an appeal to the Malaysian Supreme Court against extradition to the United States on money laundering charges.

He has been charged with four money laundering charges and with money laundering conspiracy. The charges relate mainly to his work in Singapore.