Four people have been confirmed dead and at least 50 others missing in a mud-rock flow triggered by heavy rain in Kangding County, southwest China's Sichuan Province, authorities said on Thursday.

Xiang Luo, Party chief of Kangding County, told Xinhua by telephone Thursday evening that four were killed, four injured and 50 others missing in the disaster early Thursday.

About 600 rescuers are searching for the missing.

Xiang, who is coordinating the rescue operation at the scene, said the four dead and four injured were staff of China Road and Bridge (Group) Company and Sinohydro Bureau 7 Co., Ltd.

The missing were mainly migrant workers and project staff for a rebuilding project for national highway 211, and their family members, according to Xiang.

The family members of the dead and missing were on their way to Kangding.

Ninety-seven residents stranded by a barrier lake formed by the mud-rock flow have been transferred to safe places. Residents downstream were also evacuated.

Rainstorm hit Kangding around 1:00 AM on Thursday, triggering a mud-rock flow at around 3:00 AM near the highway. A barrier lake, 3,000 meters long and 50 meters wide formed.

The National Disaster Reduction Commission and the Ministry of Civil Affairs had dispatched working teams to Kangding.

The river was no longer blocked and the barrier lake would pose little threat as of Thursday afternoon, the Ministry of Civil Affairs said.

(Xinhua News Agency July 24, 2009)