In the last three weeks, two US citizens have been detained by the North Korean regime.
According to CNN, both men work at Pyongyang University of Science and Technology, one of the few schools to employ foreign experts in North Korea.
Kim Hak-song, an ethnic Korean, born in Jilin, China, and educated at a university in California, was detained Saturday on suspicion of "hostile acts" against the regime.
Kim Hak song，朝鲜族，出生在中国吉林，在加利福尼亚的一所大学接受教育，周六涉嫌反对政权的“敌对行为”而被拘留。
In April, Kim Sang Duk, also known as Tony Kim, was also detained for "hostile acts" while trying to fly out of Pyongyang International Airport.
四月，Kim Sang Duk，又名Tony Kim，在平壤国际机场也因“敌对行为”被拘留。
The detentions also come amid heightening tensions on the Korean Peninsula.
Just last week, North Korea state media published an 1,800-word report accusing the US and South Korea of plotting to kill leader Kim Jong Un.