Vice Unification Minister Suh Ho visited a western border region on Tuesday as part of efforts to deal sternly with the controversial campaign to fly propaganda leaflets into North Korea, the ministry said.

Suh will visit Seokmo Island in the Ganghwa area on the country's western border to take a firsthand look at the preparedness of police and the coast guard to stop North Korean defectors and other activists from sending leaflets into the North, according to the ministry.

The planned visit comes hours after the General Staff of the North's Korean People's Army said that it is reviewing plans to station its troops again in areas disarmed under inter-Korean agreements and open western border areas to cooperate for a "large-scale leaflet scattering struggle against the enemy."

North Korea has lambasted South Korea almost daily in recent weeks, denouncing leafleting as a hostile act that violates a series of peace agreements.

On Saturday, Kim Yo-jong, the powerful sister of North Korean leader Kim Jong-un, threatened that Pyongyang will take a "next step" against the South and gave an instruction for the army to take necessary measures.

South Korea has advised against the sending of such leaflets by activists, citing concerns about the safety of residents in the regions as they could be vulnerable to the North's retaliatory military action. The groups have occasionally ignored the government, arguing that it is part of their right to freedom of expression.

Despite the government's repeated warnings against such activity, some defector groups are planning to send leaflets into the North. Police have been stationed in border areas to block unauthorized leafleting and any possible clashes between activists and local residents.

Earlier this month, an association of mayors from border areas called on the unification ministry to come up with stricter regulations to stop leafleting, saying that it "crushes the dreams of the people in the border areas hoping to live safely and peacefully without any tensions."

Suh is also scheduled to visit another western border area of Gimpo on Thursday. (Yonhap)