LHASA - A landslide has blocked a river and led to the build up of large bodies of water flooding a mountainous highway in Southwest China's Tibet autonomous region, cutting off traffic and trapping more than 300 travelers, local authorities said Sunday.

The landslide hit the highway linking Tibet with neighboring Sichuan province late Saturday afternoon, a spokesman with the traffic authorities in Markam county in eastern Tibet said.

The barrier lake to date is 150 meters long, 60 meters wide and 30 meters deep, the spokesman said.

More than 100 vehicles have been trapped by the lake on the lower section of the zigzag mountainous highway, he said.

Local authorities have dispatched emergency crews to defuse the threat of the lake and arrange the transfer of the trapped travellers, he said.

But continuous heavy rainfall has added difficulties to the operation, he said.

No casualties and property losses have been reported.