Massive landslides following Monday's 7.8-magnitude earthquake have dammed rivers and lakes in several counties of southwest China's Sichuan Province, posing threats to downstream areas, the water conservancy authority said on Sunday.

Twenty-one landslide blockages had been reported in the counties of Beichuan and Anxian counties in the city of Mianyang, Qingchuan county of Guangyuan, Mianzhu and Shifang cities of Deyang, and Pengzhou city near the provincial capital Chengdu.

River waters overflowed three of the blockages in Qingchuan county on Sunday morning, but posed no danger, the local relief headquarters said.

The most dangerous build up of water, about 3.2 kilometers upstream from Beichuan county seat, measured nine km long, 200 to 250 meters wide and 40 meters at the deepest sections.

With an estimated volume of 30 million to 40 million cubic meters, it was a major threat to the Beichuan county seat and its downstream areas, the Sichuan provincial water conservancy bureau said.

Another seven landslide blockages were found in Beichuan county, about 160 km from the epicenter, Wenchuan. The quake killed at least 7,000 people in the county.

People were evacuated from the areas as a precaution from Friday.

At least two water conservancy specialists are monitoring each of the blockages, accompanied by at least 10 People's Liberation Army personnel.

Monday's quake and the thousands of aftershocks damaged some water storage facilities in Sichuan Province, though no burst reservoirs were reported.

The Ministry of Water Resources has sent 25 work teams to monitor the reservoirs and prevent disasters, the ministry's chief engineer Liu Ning said on Sunday.

China's quake death toll rose to 32,477 as of 2 p.m. on Sunday, including 31,978 in Sichuan. An additional 220,109 people were injured nationwide, according to the emergency response office of the State Council.

(Xinhua News Agency May 18, 2008)