A mobile battalion in the Chinese city of Dandong on the border with North Korea is engaged in a winter tactical exercise, the official Xinhua news agency reported on Wednesday.
The exercise will continue for 15 days until early next year.
According to Xinhua, it is aimed at "improving the capability of rapid response to contingencies in cold weather by practicing mountain searches, stop-and-search practices, and counterterror operations."
But the drill apparently aims at dealing with any mass defections from North Korea amid growing instability in the North after the execution of former eminence grise Jang Song-taek.
Since Jang's execution early this month, China has conducted a flurry of military exercises on the ground and in waters surrounding North Korea.
The Shenyang Military Region, which would be mobilized in an emergency on the Korean Peninsula, deployed some 3,000 soldiers in cold-weather exercises between Dec. 4 and 11 around Mt. Baekdu, which marks the border with North Korea.
And from Dec. 6 to 20, the Chinese Navy banned ships from Bohai Bay and the West Sea across the Korean Peninsula due to drills in those areas.
"China has stepped up vigilance in the border area since Jang's execution," a source in Beijing said. "It seems security forces are on alert in major border areas."
The number of defectors crossing the Apnok or Duman River has drastically decreased.