Malaysia on Saturday recalled its envoy to Pyongyang amid heightened diplomatic tension triggered by the assassination of North Korean leader Kim Jong-un’s half-brother Kim Jong-nam, Reuters reported. Malaysia also summoned North Korea’s envoy, Kang Chol (pictured above), for saying Kuala Lumpur authorities were colluding with “external forces” in the handling of the investigation.

Kuala Lumpur officials said they were on lookout for four accused who had fled the country after the assassination, after having arrested one North Korean man, a Vietnamese woman, an Indonesian woman, and a Malaysian man. Meanwhile Japanese broadcaster Fuji TV released a video believed to be airport CCTV footage of the incident.

Pyongyang is yet to make a statement on the assassination of Kim Jong-nam, but its envoy has demanded that Kim Jong-nam’s body be handed over to North Korea immediately. Malaysia’s refusal to do so has strained one of the few bilateral relations North Korea has with other countries.

South Korea has accused the North of planning the murder and termed it “an intolerable crime against humanity and terrorist act” The New York Times reported. Senior Malaysian government officials had said that Kim Jong-nam had told medical workers on his way to the hospital that he had been attacked with a chemical spray.

Pyongyang’s ambassador had said Malaysian officials may be “trying to conceal something” and “colluding with hostile forces” and demanded that the body be handed over to Pyongyang immediately. He said North Korea will reject the results of the examination. Malaysian officials had said they had conducted a second autopsy of Kim Jong-nam, after the first examination proved inconclusive.

Kim Jong-nam, the eldest son of late dictator Kim Jong-il, had challenged his half brother’s succession to the top post. Officials said he had been trying to take over the administration. He had been living in Macau under Chinese protection after a reported dispute with his father over his attempt to enter Japan with a fake passport, South Korea’s intelligence agency told its parliament.

China, another North Korean ally, announced that it had suspended coal imports from the country following a recent missile test.