Malaysia has blocked North Korean diplomats from leaving the country in a tit-for-tat move after North Korea barred all Malaysians from exiting the Hermit Kingdom on Tuesday. The bans come as the diplomatic spat between the two countries over Kim Jong Nam’s assassination escalates, with each country expelling the other’s ambassador in recent days. The North Korean foreign ministry notified the Malaysian embassy of the latest measure Tuesday, saying all Malaysians will be blocked from leaving until the safety of North Koreans in Malaysia is guaranteed, Pyongyang’s state media said Tuesday. It’s unclear if the ban will apply to Malaysian diplomats, and no statistics were provided on the number of Malaysians currently in North Korea. Malaysia offered a swift response, with the deputy prime minister announcing a retaliatory ban against North Korean diplomats. The two countries have been butting heads as Malaysian police continue their investigation into the Feb. 13 murder of Kim Jong Un’s half-brother at Kuala Lumpur’s airport, a crime widely believed to have been carried out by the North Korean government. Malaysia has not directly accused North Korea of being behind the killing but has identified seven North Korean suspects in the crime, including a diplomat.