South Korea's police said on Sunday that they have detained a North Korean defector for attempting to cross into North Korea.

According to the police, the man in his 30s was caught entering a military unit in Cheorwon, Gangwon Province, at around 9 a.m. on Thursday in an attempt to cross into the North. He reportedly had four mobile phones and a cutting machine when he was caught.

Military authorities handed over the custody of the detainee to police given that he is a civilian.

Police said that the man defected to the South in 2018 and has lived in Seoul.

Investigation is under way to determine why and how he was trying to return to the North.