Mongolia detained four North Koreans this month for illegally entering the country, immigration authorities announced Wednesday, in a rare press release from a country that usually helps defectors by allowing them to travel elsewhere once they cross the border.

“On the 10th of May, four citizens of the Democratic People's Republic of Korea were found illegally crossing from the People's Republic of China to our country,” the General Authority for Border Protection stated in a press release that has since been deleted from its website.