North Korea said on Saturday it was questioning a student from New York University alleged to have illegally entered the country from China last month.

The Associated Press (AP) named him as 21-year-old Won Moon Joo.

Pyongyang claimed he had permanent residency in the US and lived in New Jersey.

Joo was arrested on April 22 after crossing the Amnok River from the Chinese town of Dandong, according to the official Korean Central News Agency.

The agency also said he was being questioned by state authorities and had admitted that his actions were in violation of North Korean law.

An anonymous official from South Korea's Unification Ministry said they couldn't confirm whether Joo was a South Korean citizen and was being held in North Korea.

Pyongyang has detained South Koreans, Americans and other foreigners in recent years, often over allegations of spying.

lw/rc (AP, AFP)