A sweep of chilly air has lashed northern China over the past two days, causing a major drop in temperatures.

The Ejin Banner area of the Inner Mongolia Autonomous Region has seen temperatures go as low as minus-7 degrees. Sheets of ice have been formed on frozen river surfaces.

Northeast China's Liaoning Province switched on the heat for residents on Tuesday after this winter's first snow in the region.

Authorities say temperatures will gradually rise in the following days after the cold front leaves.

Cold snap sweeps northern China