Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

North Korea released a New York University student who holds a U.S. green card Monday, six months after capturing him crossing into the country from China, South Korea's Unification Ministry said.

The release of Joo Won-moon, who is a South Korean national, came days before the North celebrates the 70th anniversary of the ruling Workers' Party on Saturday.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

A unification ministry official said Joo was handed over at the Panmunjom truce village along the heavily militarized border at around 5:30 p.m. Seoul time (2:30 a.m. ET). South Korean authorities will question him on his stay in the North, the official said.

Joo was caught in April crossing from the Chinese side of the Yalu River, North Korea's official KCNA news agency has said. Joo had admitted violating North Korean law but said he had been treated well while being held, KCNA said recently.

Joo Won-moon (C) is shown at the truce village of Panmunjom on Monday. YONHAP / Reuters

Joo, 21, has appeared on North Korean media and said he was in good health.

North Korea holds three other South Koreans and also a Korean-Canadian pastor, who was detained in February and according to North Korean state media confessed to crimes aimed at overthrowing the state.

South Korea welcomed the release of Joo and urged the North to free its other three nationals.

North Korea's highest court in June sentenced two of the South Koreans, who were accused of spying, to hard labor for life, calling the punishment a lesson for those who conspire with Washington and Seoul.

North and South Korea agreed in August to improve ties, after a standoff that threatened to become a armed conflict. Later this month, families separated by the 1950-1953 Korean war will meet for a reunion, the 20th such event.