Police on Friday searched the house and office of a former North Korean defector who has been at the center of the anti-Pyongyang leafleting campaign in South Korea, denounced vehemently by North Korea.

The national security probe team of the Seoul Metropolitan Police Agency dispatched officials to search the home and office in Seoul of Park Sang-hak, who heads Fighters for a Free North Korea, an activist group that has been leading the campaign to send anti-North Korean propaganda leaflets across the border.

The police officials combed through Park's places in Songpa Ward, eastern Seoul, to secure potential evidence.

"The search is part of efforts to seize materials so that we could verify if Park's activities are in breach of law," a police officer said.

Defying the government's warning against the cross-border leafleting campaign, Park claimed that activists from his group sent some 500,000 leaflets carried by 20 large helium balloons over to the North on Monday night.

The campaign to scatter leaflets that carry criticism of the North Korean political system and North Korea's ruling Kim family has recently been the major source of confrontations between South and North Korea. (Yonhap)