North Korea notified South Korea on Monday of its plan to repatriate two South Koreans, alleged to have illegally entered the communist nation, later this week, Seoul was quoted by Yonhap news agency as saying.

In a fax message, the North said it will send a 59-year-old man, only identified by his surname, Lee, and a 51-year-old woman, surnamed Jin, back to the South on Wednesday via the truce village of Panmunjom that sits on the inter-Korean border, according to the unification ministry.

The North said they "illegally" entered its soil in May without elaborating on when or why they did so.

The ministry said it accepted Pyongyang's proposal.

The government had tried to find out their whereabouts after learning the two South Koreans disappeared in Chinese areas bordering North Korea during their trip to China, it added.

"The government plans to check their health conditions and identify why they entered the North after taking them into custody," the ministry said in a press release.

North Korea has detained four other South Koreans, including a New York University student, spurning Seoul's request to set them free.

Joo Won-moon, a 21-year-old student, has been detained by North Korea since April 22 after illegally entering there. North Korea has also kept in captivity three other men -- missionary Kim Jung-wook, Kim Kuk-gi and Choe Chun-gil.

Pyongyang has rejected Seoul's repeated demands for their repatriation, according to the ministry.