Seoul (Reuters): North Korea barred Malaysians from leaving the country on Tuesday, sparking tit-for-tat action by Malaysia, as police investigating the murder of Kim Jong Nam in Kuala Lumpur sought to question up to three men hiding in the North Korean embassy.

Malaysia was outraged by the murder of the North Korean leader's estranged half brother at Kuala Lumpur International Airport on Feb. 13 by assassins using VX nerve agent, a chemical listed by the United Nations as a weapon of mass destruction.

Police have identified eight North Koreans wanted in connection with the murder , including a senior North Korean diplomat and a state airline employee - two of the three believed to be hiding in the embassy. The only people charged so far are a Vietnamese woman and an Indonesian woman.

As the row escalated on Tuesday, North Korea 's foreign ministry issued a temporary ban on Malaysians leaving in order to ensure the safety of its own diplomats and citizens in Malaysia.