North Korea announced on Saturday that it had arrested a South Korean student for allegedly attempting to illegally enter the country, the Wall Street Journal reports. The prisoner, according to state media, is Joo Won-moon—a 21-year-old permanent resident of the United States and New York University student.

According to the Journal, the North Korean state media said that it had detained Joo in late April when he attempted to cross North Korea’s border with China from the city of Dandong.

The South Korean government has not been able to independently confirm the state’s account, the Journal reports:

The state-run Korean Central News Agency said Mr. Joo had allegedly admitted his entry to North Korea was a serious violation of the law. He is now under investigation, the report said.

A New York University spokesman, John Beckman, told the New York Times that a student named Won Moon Joo was a junior at the Stern School of Business, but he was not taking classes this semester. “The university was unaware of his travels,” Beckman said.

Photo credit: Getty Images. Contact the author of this post: brendan.oconnor@gawker.com.