Kim Jong Nam death

North Korean state media reported Tuesday that Pyongyang will not allow Malaysian nationals inside North Korea to leave until Kuala Lumpur guarantees the safety of its own diplomats and citizens in Malaysia.

Of the Malaysians believed to be in North Korea, four are embassy staff and their families, plus two United Nations employees, a Malaysian government official told CNN.

"This abhorrent act, effectively holding our citizens hostage, is in total disregard of all international law and diplomatic norms," Malaysian Prime Minister Najib Razak said in a statement Tuesday.

In a televised address, South Korean lawmaker Kim Byung-kee said North Korea's foreign ministry and ministry of national security plotted the murder of North Korean leader Kim Jong Un's half-brother.

"The assassination of Kim Jong Nam was an act of systematic terror ordered by Kim Jong Un," Kim said. "The operation was conducted with two assassination groups and one supporting group."

The suspect is one of two women whom Malaysian authorities believe swiped the face of Kim Jong Nam with the VX nerve agent that led to his death while he was waiting to catch a flight February 13 at Kuala Lumpur International Airport.

Indonesian authorities were able to meet with suspect Siti Aishah, an Indonesian citizen, for the first time Saturday.

Aishah thought the substance she rubbed on Kim's face was "a kind of oil, baby oil, something like that," said Andreano Erwin, Indonesia's deputy ambassador to Malaysia.

However, in a news conference Wednesday, Bakar said North Korean authorities were not cooperating.

Bakar also said that security had been increased at the mortuary where Kim's body is being held after an attempted break-in.

Kim Jong Nam was the half-brother of North Korean leader Kim Jong Un. He died last Monday after a suspected poisoning at Kuala Lumpur International Airport 2.

Developing story - more to come

Authorities said they are treating the incident as a murder case.

Top police official Noor Rashid Ibrahim addressed reporters in Kuala Lumpur on Sunday. When asked whether Malaysian authorities thought Kim's death had been ordered by the North Korean regime, he said only that "the four hold North Korean nationality, that is all."

Kim Jong Nam was on his way to catch a flight Monday morning to see his family in Macau when he died. Police say he was sprayed with poison as he waited to board the flight at Kuala Lumpur International Airport.