Thursday night's heavy rain triggered mud-rock flows, disrupted traffic on a pivotal highway to Tibet and killed two people in the neighboring Sichuan Province, local authorities said Friday.

The path for pedestrian at the Donghekou Earthquake Relics Park is flooded in Qingchuan County, southwest China's Sichuan Province, July 15, 2009. Heavy rains that began on Tuesday have killed one people and caused the other missing in Qingchuan County. [Xinhua]

The road traffic arm of Tibet's regional police sent 20 road workers and two cranes for repair work on a narrow, zigzagging section of the Sichuan-Tibet Highway in Tibet's Nyingchi Prefecture.

As of midday Friday, more than 100 vehicles were stranded in the Nyingchi section of the highway, said police officer Chen Jun.

Chen said the repair work reported little progress as rocks were still rolling down the mountains, posing a threat to the road workers. "No casualties were reported as yet, and we expect traffic to resume after 6 p.m.."

Heavy rain hit most parts of China Thursday and Friday, relieving the prolonged drought in the northern regions but escalating flood alarms in the south.

In the southwestern Sichuan Province, heavy rain has lasted into the fourth day. Two people were killed Thursday, including a woman from Pingwu County who was knocked down by rolling rocks from a mountain, and a man from Qingchuan County who was buried underneath a landslide.

In Qingchuan, another man was listed as missing after he was washed away by a flash flood, the local government said.

In the worst-hit cities of Chengdu, Guangyuan and Mianyang, average rainfall in the 26 hours from 8 a.m. Wednesday to 10 a.m. Thursday exceeded 200 mm, the provincial weather office said.

The provincial government warned the rain, flood and subsequent geological disasters were posing further threats to most cities and counties, which were still rebuilding after last year's devastating earthquake.