The rescue operation to find 50 people missing after a landslide that has killed at least four in Kangding, southwest China's Sichuan Province, was hampered Friday as the only highway to the scene was blocked by stones.

The stones, intended for building a hydropower station project, were flushed onto the highway -- keeping large rescue machines from reaching the site.

Rescuers have to climb through the slope while watching out for stones that kept falling down.

More than 100 rescuers were searching through the rubble with shovels, portable lifting jacks and cutting machines for the missing people.

About 30 rescuers were seen trying to move an overturned truck to search for bodies. But their efforts were in vain without the help of large machines.

The disaster was triggered by heavy rains Thursday in Kangding County. A total of 136 temporary sheds for workers of the hydropower station project were buried by 500,000 cubic meters of mud and rocks, according to rescuers.

Sichuan Governor Jiang Jufeng and other senior officials are at the site to coordinate the rescue operation.

(Xinhua News Agency July 24, 2009)