GOVERNMENTS often expel foreigners who enrage them. North Korea offers a worse fate: not being allowed to leave. On March 7th authorities in Pyongyang, the capital, said that 11 Malaysian citizens living in North Korea would be prevented from flying home until the two countries had resolved their differences over the murder of Kim Jong Nam—the half-brother of Kim Jong Un, the North’s dictator. Kim Jong Nam was assassinated last month at Kuala Lumpur’s main airport using VX, a nerve agent renounced by nearly all governments except North Korea’s. The North later released two of the hostages, but continued to hold the other nine.

Najib Razak, Malaysia’s prime minister, condemned North Korea’s decision to detain its citizens as “abhorrent”. He announced that North Koreans in Malaysia—of whom there are perhaps as many as 1,000, many doing dirty jobs such as mining—would in turn be prevented from leaving until the regime backed down. Malaysian authorities are watching who enters and leaves North Korea’s embassy in Kuala Lumpur. The chief of police believes that at least two North Koreans wanted for questioning about Kim Jong Nam’s murder are hiding inside; he has said that his men will stand guard for “five years” if it takes that long for them to come out.

The stand-off caps a week of diplomatic drama. On March 6th Malaysia kicked out the North Korean ambassador, Kang Chol, who denies that North Korean spies were responsible for the murder or that the victim was Kim Jong Nam; he accused Malaysia of cooking up the story with America and South Korea to blacken the North’s reputation. The North Korean government formally expelled Malaysia’s ambassador the same day, though by then his bosses had already called him back to Kuala Lumpur.

In a further display of recalcitrance, North Korea tested four missiles simultaneously on March 6th, in defiance of UN sanctions. In response to the North’s frequent tests, America and South Korea are accelerating the deployment in South Korea of THAAD, an American anti-missile system. That, in turn, has riled China, which fears THAAD could render its missiles less potent, too.

Meanwhile, on March 8th, a previously unknown outfit called Cheollima Civil Defence posted a video it said was of Kim Han Sol, the son of Kim Jong Nam. It claimed to have responded to a request to “extract and protect” him from his home in Macau, along with his mother and sister. The group said it had received help from China, America and the Netherlands. Whether Kim Han Sol will become a vocal critic of the regime that murdered his father, or choose to vanish from sight, remains unclear.