North Korea has banned Malaysians inside its country from leaving, in a growing diplomatic row over the killing of Kim Jong-nam.
In response, Malaysia has banned North Korean embassy officials from leaving, saying it “needs to be done”.
The tit-for-tat actions come amid North Korean fury at Malaysia’s investigation into Mr Kim’s death.
Mr Kim, the estranged half-brother of North Korea’s leader, was killed in Malaysia last month.
While Malaysia has not directly blamed the North Korean government for the attack, there is widespread suspicion Pyongyang was responsible.
North Korea has fiercely denied this and has accused Malaysia of mishandling the investigation and colluding with its enemies.
The row over the killing – and over who has the right to claim Mr Kim’s body from the mortuary where it is being held – has rapidly escalated over the past two weeks.
Both Malaysia and North Korea have already expelled each other’s ambassadors, when on Tuesday North Korea announced it was temporarily banning any Malaysians currently in its country from leaving, citing security reasons.
The state news agency KCNA said the ban would stay in place “until the incident that happened in Malaysia is properly solved”, but that Malaysians in the country would be able to carry on their lives as normal.
Hours later, Malaysia’s Deputy Prime Minister Ahmad Zahid Hamidi responded by saying North Korean embassy staff and officials would not be allowed to leave.
“We don’t mean to do this, but it needs to be done,” the Malaysia Star quoted him as saying.
“We need to take similar steps as they have manipulated the murder.”
It was not immediately clear how many people would be affected by each of the bans.
A post-mortem examination on Mr Kim’s body found he was killed by a dose of VX nerve agent the most potent of all known chemical weapons, as he waited to board a flight to Macau on 13 February.
So far, only two people – an Indonesian woman and a Vietnamese woman – have been charged with murder.
A detained North Korean was released last week because of lack of evidence, but Malaysia is seeking a number of other North Koreans.
On Tuesday, Malaysia’s police chief Khalid Abu Bakar said he believed two of those suspects were hiding inside the North Korean embassy compound in Kuala Lumpur.
“We will wait and if it takes five years we will wait outside, definitely somebody will come out,” he told reporters on Tuesday.
Pyongyang has not yet confirmed that the body is that of Kim Jong-nam, acknowledging him only as a North Korean citizen. Mr Kim was travelling using a passport under a different name.