North Korea banned Malaysians from leaving the country Tuesday, triggering a tit-for-tat response from Kuala Lumpur which said its citizens were effectively being held "hostage" in the row over the assassination of Kim Jong-Nam.
Pyongyang's extraordinary move came as it faced growing international condemnation for a volley of missiles it fired into the Sea of Japan, defying stringent global sanctions aimed at halting its weapons programme.
Tuesday's developments marked a dramatic heightening of tensions with Malaysia three weeks after the half-brother of North Korean leader Kim Jong-Un was murdered at an airport with the banned VX nerve agent.
Kim Jong-Nam assassination: diplomatic fallout
The North decided to "temporarily ban the exit of Malaysian citizens in the DPRK", the official news agency KCNA said, citing the foreign ministry and using the North's official name, the Democratic People's Republic of Korea.
The prohibition would remain in place "until the safety of the diplomats and citizens of the DPRK in Malaysia is fully guaranteed through the fair settlement of the case that occurred in Malaysia".
The Malaysian foreign ministry said 11 of its citizens were currently in North Korea, including three embassy staff, six family members and two others who work for the UN's World Food Programme.
Malaysian Prime Minister Najib Razak condemned the bar, and said he was ordering a similar ban on the movement of "all North Korean citizens in Malaysia". Analysts said they could number around 1,000.
The home ministry had previously indicated the ban only affected diplomats and embassy officials.
"This abhorrent act, effectively holding our citizens hostage, is in total disregard of all international law and diplomatic norms," Najib said, according to a statement.
"As a peace-loving nation, Malaysia is committed to maintaining friendly relations with all countries.
"However, protecting our citizens is my first priority, and we will not hesitate to take all measures necessary when they are threatened."
- Weapon of mass destruction -
Pyongyang and Kuala Lumpur had unusually strong links for years, but ties have rapidly degenerated in the weeks since Kim Jong-Nam was attacked at a Malaysian airport by two women who wiped a deadly chemical on his face.
An autopsy revealed that to be VX nerve agent, a substance so dangerous it is classed as a weapon of mass destruction by the UN.
Pyongyang has banned Malaysians from leaving North Korea until a row over the assassination of Kim Jong-Nam is resolved 
Seoul has blamed Pyongyang for the assassination, and Kuala Lumpur wants to question several North Koreans, although the only one it arrested was released last week for lack of evidence.
The North has never confirmed the dead man's identity, but has denounced the Malaysian investigation as an attempt to smear it.
Kuala Lumpur announced the expulsion of the North's ambassador over the weekend. He flew to Beijing on Monday, after launching a final verbal assault on his hosts.
Kang Chol slammed what he called a "pre-targeted investigation by the Malaysian police". Photographs later showed him sitting in the economy section of the plane.
Pyongyang retaliated by formally ordering out his counterpart -- who had already been recalled for consultations.
According to KCNA, the foreign ministry expressed hopes that the Malaysian government would solve the issue "as early as possible" from a position of "goodwill" and "setting store by and developing the bilateral relations".
Malaysian diplomats and nationals in the North "may work and live normally under the same conditions and circumstances as before" while the travel ban is in place, it added.
The escalating row comes as the United Nations Security Council scheduled an emergency meeting to coordinate the global response to the North's latest missile launches, which KCNA said Tuesday were trial runs at hitting "the bases of the US imperialist aggressor forces in Japan".
Three of the four projectiles fired Monday came down provocatively close to Japan, in what observers said was a test of US President Donald Trump's inchoate North Korea policy.
In phone calls to his Japanese and South Korean counterparts, Trump reaffirmed Washington's "ironclad commitment" to its allies.
The US will demonstrate to Pyongyang that there were "very dire consequences" for its actions, the White House said in a statement.
Under UN resolutions, Pyongyang is barred from any use of ballistic missile technology, but six sets of sanctions since its first nuclear test in 2006 have failed to halt its drive for what it insists are defensive weapons.
New US Secretary of State Rex Tillerson will visit Japan, China and South Korea later this month, a weekend report said, with North Korea expected to top his agenda.

Source: AFP