Another 100,000 people may be moved from the area around China's massive Three Gorges Dam because of landslides and bank collapses, state media say.
They quote a government official as saying that the number of geological disasters had increased dramatically since the dam on the Yangtze River reached its maximum level in 2010.
About 1.4m people have already been relocated from the area.
The world's largest dam is said to have cost up to $40bn (£25bn) to build.
Hazardous sites
Some 100,000 people may be moved from the area in the next three to five years, Liu Yuan, an inspector at China's ministry of land resources, told China National Radio.
Mr Liu said the authorities would try to stabilise 355 locations around the dam where rockfalls and landslides had already happened.
Another 5,386 hazardous sites were being monitored.
The water in the huge reservoir rises and falls depending on the season, making the banks unstable, the BBC's Michael Bristow in Beijing reports.
The banks have already collapsed in hundreds of places, our correspondent says.
China's revolutionary leader Mao Zedong dreamed of building the Three Gorges Dam.
Construction started in 1994 and was completed in 2006, with the reservoir reaching its full height two years ago after submerging 13 cities, 140 towns and 1,350 villages.
But the government has already admitted it has not done enough for those forced to move, our correspondent adds.
BBC News - China's Three Gorges Dam may displace another 100,000
