North Korea has installed surveillance cameras and reinforced barbed wire in its northern border areas close to China to try to stem the flow of defections of its people and stop the influx of foreign influences, a source familiar with the issue said Tuesday.

The measures were taken near the North Korean town of Sinuiju, the northeastern city of Hyesan and other border areas, said the source.

The latest crackdowns on defectors came as North Korean leader Kim Jong-il called for a thorough inspection of residents during his trip to Sinuiju last month, the source said.

While visiting Sinuiju on July 1-6, Kim also criticized residents in the Chinese border city and nearby areas for being influenced by capitalism, citing disorder and the way local residents dressed.

Sinuiju and other porous border areas have served as key routes through which a stream of North Koreans continues to flee to China for eventual defections to South Korea, home to more than 21,000 North Korean refugees.

Some people in the border areas are also at the forefront of spreading outside news through mobile phones smuggled from China that could be used to communicate with people in China and South Korea.

The move prompted the North Korean authorities to inspect people’s use of mobile phones, television and radio to try to stop any communication with the outside world.

North Korea is a tightly controlled society and its people are officially forbidden from listening to news from the outside.

The dials on radios and televisions are fixed so that only state broadcasts can be heard, though many North Koreans are believed to be secretly watching or listening to South Korean television and radio broadcasts.

The development comes as North Korea is trying to keep outside influences from seeping into the isolated country out of fear that they could pose a threat to leader Kim Jong-il’s plan to hand over power to his heir apparent son Kim Jong-un.

The 69-year-old leader named Jong-un vice chairman of the Central Military Commission of the North’s ruling Workers’ Party and a four-star general last year in the clearest sign yet to make his son the next leader.

The succession, if made, would mark communism’s second hereditary power transfer. The elder Kim inherited power from his father, the country’s founder Kim Il-sung, who died in 1994.

The North’s latest move to block foreign influences demonstrated its concern about any possible popular uprising similar to the ones in North Africa and the Middle East that ousted longtime autocratic leaders earlier this year.

In February, the North’s leader-in-waiting Kim Jong-un reportedly ordered the punishment of any violators of the law.

North Korea has conducted probes into family members of defectors and missing people near the border areas and sent them to remote places. The crackdowns on defectors have also caused jitters among security and other officials.

In June, a security official reportedly committed suicide in Hyesan after being accused of aiding defectors and of smuggling. 

(Yonhap News)