the transit of some North Korean refugees to Seoul. Four of the biggest defector safehouses in Vietnam were run by South Korean expatriates. In July 2004, 468 North Korean refugees were airlifted to South Korea in the single largest mass defection; Vietnam initially tried to keep their role in the airlift secret, and in advance of the deal, even anonymous sources in the South Korean government would only tell reporters that the defectors came from "an unidentified Asian country". Following the airlift, Vietnam tightened border controls and deported several safehouse operators. In June 2002, 17 North Korean defectors were reportedly captured by Vietnamese border forces and deported to China. 5 North Korean defectors who surrendered to the Ho Chi Minh City police in May 2004 in an appeal to go to South Korea were reportedly deported to China by Vietnamese authorities on 16 June. On 25 June 2012, a South Korean activist surnamed Yoo was arrested in Vietnam for helping the North Korean defectors to escape. He was reportedly released after 8 days and then deported to Seoul. 9 North Koreans were arrested on 22 October 2015 and then reportedly deported to the Chinese city of Shenyang. In April 2019, 6 North Koreans were stopped by Vietnamese military authorities in the province of Ha Tinh; 3 managed to escape while the other 3 were reportedly deported to China. On 23 November 2019, 14 defectors who had left China 2 days earlier were caught in Vietnam as they attempted to make their way to Laos. The Vietnamese authorities returned the group to China on 28 November. 10 of the original 14 were caught again in Vietnam the next day. According to a Seoul-based activist group in January 2020, 11 North Koreans detained in Vietnam while seeking to defect to South Korea were released with the help of European institutions. A Wall Street Journal report said that US officials had intervened to secure the defectors' release; the report's accuracy was questioned by South Korea's Foreign Ministry and the activist group's leader. Psychological and cultural adjustment North Korean defectors experience serious difficulties connected to psychological and cultural adjustment once they have been resettled. This occurs mainly because of the conditions and environment that North Koreans lived in while in their own country, as well as inability to fully comprehend new culture, rules, and ways of living in South Korea. Difficulties in adjustment often