Seoul, Jun 11 (IANS): South Korea's Unification Ministry on Thursday filed a criminal complaint against two North Korean defector groups for sending anti-Pyongyang leaflets across the border, officials said.

The move came days after the North defined the South as an "enemy" and vowed to cut all inter-Korean communication lines in anger over the anti-Pyongyang leaflets, reports Yonhap News Agency.

The Ministry said it filed a complaint with the Seoul Metropolitan Police Agency against the two defector groups -- Fighters for Free North Korea and Keunsaem -- for sending leaflets and plastic bottles filled with rice into the North.

According to the Ministry, sending leaflets and bottles into the North constitutes a violation of the inter-Korean exchange and cooperation act that bans sending goods to North Korea without government permission.

It also accused the groups of violating the aviation safety act and the public waters management act.

The Ministry said it decided to revoke business permits from the two groups.

North Korean defectors and anti-Pyongyang activists have for years sent a large number of leaflets via giant balloons, said the Yonhap News Agency.

North Korea has bristled at such activities, saying they are aimed at tarnishing its leader.

The government has advised against sending such leaflets, citing concerns about the safety of residents in the border regions, but they have often ignored such an appeal, citing their right to freedom of expression.