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, North Korean state media reported Tuesday.
The 11 Malaysians believed to be in North Korea include four embassy staff members and their families and two UN 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.
Malaysia retaliated by barring all North Korean citizens from leaving Malaysia until the country is "assured of the safety and security of all Malaysians in North Korea," he said.
Three North Koreans wanted for questioning in the February 13 killing of Kim are believed to be holed up in the North Korean Embassy in Kuala Lumpur, Malaysian police revealed Tuesday.
They include Hyon Kwang Song, the embassy's second secretary, and Kim Uk Il, a staff member at North Korean national carrier Air Koryo. Police issued an arrest warrant for the latter last week.
"It is a matter of time before they come out," Royal Malaysia Police Inspector-General Khalid Abu Bakar said. "We will wait. If it takes five years, we will wait outside."
The official told CNN that police believed another North Korean man who is wanted for questioning, Ri Ji U, is also holed up in the embassy.
Pictures outside the embassy appeared to show a police presence gathering.
It's not clear how many North Koreans are in Malaysia, but travel to the country was visa-free for North Koreans until Malaysia stopped doing so Monday.
Killing at Kuala Lumpur airport
Kim Jong Nam was killed at Kuala Lumpur International Airport by being poisoned with VX, a deadly nerve agent, according to Malaysian authorities.
South Korea is the only country that has blamed North Korea for assassinating Kim, an allegation Pyongyang has strongly denied.
However, relations between Malaysia and North Korea have deteriorated over the course of the investigation into Kim's death. Both countries have expelled their respective ambassadors.
North Korea's move to bar Malaysians from leaving warranted a retaliatory response, Malaysia's deputy leader said.
"This is what needs to be done when a country that has diplomatic relations with Malaysia does something that is beyond diplomatic norms and etiquette and Malaysia is forced to take action," Deputy Prime Minister Ahmad Zahid Hamidi said.
"We want to send a clear message to North Korea not to point fingers at Malaysia and don't belittle the status of Malaysia as a sovereign country."
2 women charged with murder
Two women have been charged with murder in Kim's death and face the death penalty if convicted: Siti Aisyah of Indonesia and Doan Thi Huong of Vietnam.
Malaysian authorities believe the North Koreans recruited the two women to kill Kim before he was set to catch a flight from Kuala Lumpur to the Chinese-controlled territory of Macau.
Police say they wiped his face with VX, which killed him in under 20 minutes.
Authorities from Indonesia and Vietnam said the women believed they were participating in a prank TV show, but Malaysian authorities said they suspect the two knew what they were doing.
Police have requested Interpol assistance in finding four other North Korean suspects who are believed to be back in Pyongyang.