SEOUL (AFP) - North Korea said on Monday it would send home two South Korean citizens who were captured last month for entering the communist country illegally.

The South's Unification Ministry in charge of cross-border affairs said it accepted the North's offer to repatriate the two on Wednesday through the border village of Panmunjom.

The North's Red Cross Society said in a message to Seoul that the two - a 59-year-old man and a 51-year-old woman - had illegally crossed the border with China on May 11, without explaining why it is sending them home.

The ministry quoted family members as saying the two went missing during a trip to China. It was not clear whether they had tried to defect to the impoverished communist country.

So far, about 28,000 North Koreans have escaped to the South since the end of the 1950-1953 Korean War, but defections in the opposite direction are very rare.

The few defectors that Pyongyang does receive have usually been allowed to stay in the secretive state.

Pyongyang sent home six South Koreans in 2013 and a 52-year-old South Korean man last year after rejecting their requests for defection.

However, it has rejected Seoul's repeated calls to free four other South Koreans, including a New York University student and three missionaries, who were detained after illegally entering the country.

The North views foreign missionaries as seditious elements intent on fomenting unrest.