China targets illegal immigration at North Korea border
China has launched a drive against illegal immigration in a north-eastern region bordering North Korea.
The campaign in the Yanbian Korean Autonomous Prefecture in Jilin province mainly focuses on North Koreans fleeing poverty and persecution at home.
China is known to routinely repatriate North Koreans who often slip across the border undetected.
Human rights groups say many face punishment when they return.
"Foreigners who illegally enter, work and overstay are hidden troubles, and they might pose potential threats to social stability," Li Yongxue, a police official from Yanbian, was quoted by state-run China Daily newspaper as saying.
The police say they want to stamp out criminal activities to maintain order. They add that those without proper documents will be sent back.
Many of these illegal immigrants have relatives in China, some come to work, while others use China as a staging post before moving to other countries, according to the BBC's Michael Bristow.
A police officer from the province told the BBC that it was a sensitive year in China, with officials stressing the need for stability ahead of a leadership change this year.