Denying its own involvement, Pyongyang on Wednesday accused Seoul and Washington of killing a North Korean, believed to be Kim Jong-un's half-brother, without acknowledging the deceased as such.

In a dispatch from Pyongyang, the North's Korean Central News Agency (KCNA) said the person was a North Korean citizen named "Kim Chol," carrying a diplomatic passport.

"The cause of his death has not yet been clearly identified but the US and the South Korean authorities are groundlessly blaming North Korea, asserting that he was intoxicated by highly-poisonous VX nerve substance," the KCNA report said. 

Kim Jong-nam was killed on February 13 at an airport in Kuala Lumpur after two women, believed to have been hired by the communist North, allegedly smeared the nerve agent on his face.

The North Korean news outlet, however, claimed the agent could not have been VX.

"World media query that if component of VX was allegedly detected from Kim Chol's eyes and lips, the ambulance that carried him and police who guarded him must have all been intoxicated and if so, the airport should have been closed, but it is still in operation," it said.

However, it accused the US and South Korea of using the nerve agent to kill the North Korean, claiming the US is one of a few countries that still possesses the substance, Yonhap reported.

"What is all the more problematic is the fact that the US is introducing into South Korea all kinds of chemical weapons."

The Malaysia police also arrested a North Korean man, Ri Jong-chol, on suspicions of smuggling in the chemical substance from North Korea and providing it for the murder of Kim.

The KCNA report claimed the murder of the North Korean citizen was an act staged by Seoul and Washington in an attempt to stir up international repugnance against the North, and thus start a nuclear war against the communist state.