Chinese officials are planning to drain a massive lake formed by this month's earthquake to prevent potential flooding, and have already told nearly 200,000 people to leave the area.
A run-off channel to drain Tangjiashan lake has been completed, and water will be discharged sometime between Sunday and Tuesday, according to Xinhua, China's official news agency.
Tangjiashan is the largest lake created by the May 12 earthquake. More than 30 were created after landslides blocked rivers in the mountainous province of Sichuan.
Xinhua reported early Saturday that 197,477 people were told to leave their homes -- roughly equivalent to everyone in the metro area of Regina.
Tan Li, the Communist Party chief of Mianyang region, had issued another evacuation order that calls for all 1.3 million people in the area to leave if "the barrier of the quake lake fully opens" and floods the region.
There are no reports that the lake's barrier is about to burst. Independent reporting is difficult because troops have sealed off the Beichuan town area to the public. Beichuan sits just below the lake.
Authorities have also worried that the 7.9-magnitude earthquake weakened existing dam structures.
The confirmed death toll from the quake is now set at 68,858. Another 18,618 people are listed as missing, said China's government.
Millions in Sichuan, about 1,300 kilometres southwest of Beijing, are living in either tent camps or prefabricated housing.
President Hu Jintao travelled to Shaanxi province, just north of Sichuan, on Saturday to check on relief efforts there, Xinhua reported.
Parts of Shaanxi also suffered damage from the quake.
With files from The Associated Press