Police remove the balloon containing anti-North Korea leaflets from the water in the valley at Hongcheon in Gangwon Province, Tuesday. Yonhap

A group of North Korean defectors in the South claimed Tuesday it sent anti-North Korea leaflets across the border overnight from the western border city of Paju.

Police said one of the balloons used for sending the leaflets was found in a town in the mountainous eastern province of Gangwon.

"(We) sent anti-North Korea leaflets over (to the North) between 11 p.m. and midnight on Monday (from a town) in Paju," Park Sang-hak, chief of Fighters for a Free North Korea, said. The group picked a very dark location to avoid police surveillance, he added.

According to Park, six members of the group, which has been active in anti-North Korea leafleting, sent to the North around 500,000 leaflets carried by 20 large helium balloons.

Some 500 pamphlets depicting South Korea's success story, 2,000 American one-dollar bills and 1,000 SD cards were also flown to the North, along with the leaflets, he said.