About 2,000 local residents were evacuated as of Saturday night in Southwest China's Yunnan province after water escaped on Friday from a barrier lake formed by an August earthquake.

Six workers are missing after the accident. Some 400 rescuers are searching at the site.

At around 3:20 p.m. on Friday, 20 people were digging tunnels to allow the water to discharge from the lake safely.

"They were about to place dynamite to blow up the blockage, but suddenly water burst through and flooded the construction site," said a Yunnan official on Saturday.

Ten workers escaped, but 10 others were washed away. Four were rescued and are being treated at Qiaojia People's Hospital.

The lake is 15 km long and covers an area of 49 square km in Qiaojia and Ludian counties. It was formed when landslides blocked the Niulan River.

The August quake left over 600 people dead and 112 missing in Yunnan.