Radio Free Asia (RFA) says that North Korea's National Defense Commission is strengthening its crackdown on foreign culture amid a sharp increase in the inflow of South Korean DVDs.

Quoting a source in the North on Friday, the Washington-funded broadcaster reported that North Korean authorities have set up an inspection team under the defense commission to monitor the circulation of South Korean DVDs. The inspection team is reportedly authorized to search the houses of even high-ranking officials of the North Korean Workers Party and the military.

Quoting an official from an organization for North Korean defectors, RFA also said that multiple North Korean men in their 20s were arrested for watching DVD footage on the sinking of South Korea’s “Cheonan” vessel and the North's artillery attack on Yeonpyeong Island.

The broadcaster added the inspection team has since launched inspections for DVDs near the border with China.