The unification ministry revoked the operation permits of two North Korean defector groups Friday, saying their campaigns to send propaganda leaflets into the communist nation "gravely hindered" efforts toward unification.

The move came a month after North Korea blew up an inter-Korean liaison office in its border city of Kaesong in anger over leaflets criticizing leader Kim Jong-un, saying such leafleting violates a series of peace agreements between the two sides.

The decision to revoke the operation permits of the two groups -- Fighters for a Free North Korea and Kuensaem -- had been widely expected because the ministry said last month it would push for the revocation and filed a criminal complaint with the police against the leaders of the two groups.

"The act of scattering leaflets and goods by these entities ... gravely hindered the government's unification policies and efforts towards unification, jeopardized the lives and safety of residents in border regions and created a tense situation on the Korean Peninsula," the ministry said in a statement.

The ministry said the leafleting campaign goes beyond the intended purpose of the groups' establishments. It also said it comprehensively reviewed various evidence, including statements from the groups, before revoking their permits.

Losing operation permits will make it hard for the groups to raise money for their operations and activities, as revocation will make them ineligible for various benefits available to registered organizations.

Sending leaflets across the border recently emerged as a major source of cross-border tensions since Pyongyang called it a violation of an inter-Korean summit agreement in 2018 and threatened to take a series of retaliatory steps against South Korea if it did stop such activity.

The government has advised against sending such leaflets, saying that such activity violates an inter-Korean exchange and cooperation act and that it also could jeopardize the safety of residents in border areas.

But they have ignored the appeal, citing their right to freedom of expression and emphasizing that their leafleting is aimed at providing information to people in the oppressive North Korean state. (Yonhap)