Only 751 North Koreans made it to the south by way of China in the first six months of 2012, down 42 percent from the same period a year earlier, The Washington Post reported Friday. Most North Koreans who leave the country escape by way of China.
Open Radio for North Korea in Seoul reports its contacts in the north say 20,000 soldiers have been transferred to the Chinese borders.
Andrei Lankov of Kookmin University in Seoul said the government has put a lot of resources into guarding the border to keep North Koreans inside the country. Most of his information comes from defectors.
"The border with China used to be essentially unguarded," he said. "It is now very closely watched."
In recent years, the number of defectors has run at about 3,000 annually, with 2,706 reaching the south last year.
Defectors have said that after Kim Jong Il died in December, North Koreans were warned that any border crossings would be severely punished during the mourning period. There appears to have been no let up in the additional security.