Jackson Free Press

SEOUL, South Korea (AP) — South Korea on Monday urged North Korea to quickly free a South Korean student of New York University detained in the North for illegally entering the country.

Pyongyang's state media said Saturday it arrested Won Moon Joo on April 22 when he illegally entered North Korea by crossing the Amnok River from the Chinese border town of Dandong. The North said that Joo, who has permanent residency in the U.S., has admitted his violation of a law and was being investigated by authorities.

Seoul's Unification Ministry said Monday that Joo is a South Korean national and it's "very regrettable" for North Korea to be detaining him without providing any prior explanation to the South Korean government and his family. Spokesman Lim Byeong Cheol told reporters that South Korea strongly demands that North Korea release Joo immediately.

A spokesman for New York University, John Beckman, confirmed that Joo was a junior at NYU's Stern School of Business, but that he was not taking classes this semester and that the university was unaware of his travels. He said the university was in touch with the U.S. State Department and the South Korean Embassy.

It's not known why Joo tried to enter North Korea. The country has occasionally arrested South Koreans, Americans and other foreigners for what it called alleged espionage and other unspecified hostile acts. In the past, authorities in Pyongyang staged news conferences involving those detained foreigners, during which they acknowledged their wrongdoing and made statements that they recant after being released.

In March, North Korea announced that it had detained two South Korean citizens over alleged espionage. It has been holding another South Korean man since late 2013 on suspicion of spying and allegedly trying to set up underground churches in the North. He was sentenced last year to life in prison with hard labor.

Lim, the South Korean spokesman, said Monday that North Korea must release those three other South Korean detainees as well.

Last year, the North released three Americans — two of whom entered the country on tourist visas — and Kenneth Bae, a Korean-American missionary who was convicted of "anti-state" crimes.