China has been building wire fences along its border with North Korea, around the source of the Duman River near Mt. Baekdu. Speculation is that they are meant to prevent defection of North Koreans to China.
The wire fences are 1.5 to 1.7 meters high and two to three meters wide T-shaped concrete pillars, similar to those along the Military Demarcation Line on the Korean peninsular.
Beijing reportedly claimed that the fence is there to stop North Korean defection. This view is widely held as many North Koreans pass the areas near Mt. Baekdu and the Duman River to flee their country.
The border fencing [may also have] something to do with the recent Sino-DPRK relations estranged by Pyongyang’s missile tests.