About 1,000 vehicles are stranded on a section of a major highway in northwest China after rain and snow left an impassable layer of ice on Thursday, say traffic authorities.

It is the second big traffic jam in two days on the highway linking Hami Prefecture of Xinjiang Uygur Autonomous Region and neighboring Gansu Province, a Hami highway traffic administration spokesman said.

About 1,000 vehicles are stranded on a section of a major highway linking Hami Prefecture of Xinjiang Uygur Autonomous Region and neighboring Gansu Province in northwest China on Thursday.

"Most of the vehicles have no snow chains, so the drivers have to stop where they are," he said.

Emergency crews from traffic and police authorities were checking on motorists and distributing free drinking water and food, he said.

"We asked some bus drivers to return to Hami to ensure passenger safety," he added.

It was not known when the traffic will be able to resume.

Hami saw sleet, which left a layer of ice on the highway, over Tuesday night. More than 600 vehicles with 1,400 people were stranded from Tuesday night to Wednesday noon, when traffic resumed.