North Korea on Tuesday barred people from Malaysia from leaving the country till the mystery shrouding the killing of Kim Jong-un’s half-brother in Kuala Lumpur is resolved. “All Malaysians will be temporarily prohibited from leaving the country until the incident that happened in Malaysia is properly solved,” read the statement issued by the country’s Foreign Ministry.

Malaysia said the ban was holding their “citizens hostage” and slapped a similar order on North Koreans in Malaysia. President Najib Razak has instructed the police to bar all North Korean citizens in Malaysia from leaving until the safety of Malaysians in North Korea was assured, reported The Guardian. While there are 11 Malaysians – three embassy staff, six family members and two others – in North Korea, Malaysia still has hundreds of North Koreans, including students and workers, according to Reuters.

Kim Jong-nam was poisoned to death at Kuala Lumpur Airport on February 13. The assassination has already strained bilateral relations between the countries and triggered diplomatic tension. On March 4, Malaysian authorities had expelled North Korea’s ambassador after he accused Kuala Lumpur of colluding with “outside powers to defame North Korea”. North Korea responded in a similar manner and declared the Malaysian ambassador persona non grata.

The Malaysian Police have named seven North Koreans in connection with the murder. On Tuesday, Malaysia’s chief of police said that two of the accused North Korean nationals were hiding in the country’s embassy. Till now, a Vietnamese woman and an Indonesian woman have been charged with murder.

Meanwhile, the United States on Tuesday deployed its advanced anti-missile defence system in South Korea, a day after North Korea fired four ballistic missiles towards the Sea of Japan. A US forces’ spokesperson in South Korea told The New York Times that one of five major components of the missile system had arrived on Monday and the system would be fully operational in a couple of months’ time.

On Monday, the US President had told South Korean and Japanese leaders that his country would stand with its Asian allies and take steps to combat North Korea’s ballistic missile threat. “Continued provocative actions by North Korea, to include yesterday’s launch of multiple missiles, only confirm the prudence of our alliance decision last year to deploy THAAD [Terminal High Altitude Area Defense] to South Korea,” said US Pacific Commander Admiral Harry Harris. North Korea’s test-fire was, on the other hand, a response to the joint naval exercises by South Korea and the US.