The earth surface sank at a construction site along the Yangtze River in central China's Wuhan City, posing a potential threat to the river bank, local authorities said on Saturday.

The subsidence began on Friday afternoon and continued on Saturday afternoon at a residential department in Hannan District about 100 meters from the river bank, according to the city's emergency office.

"There has been a 5,000-square-meter sinking area extending from east to west, with the deepest part six meters beneath the earth. Further sinking may threaten the safety of the bank," said a monitoring technician.

The accident did not cause injuries or deaths, but has stopped the construction of the residential department and damaged power supplies, according to the emergency office.

Local government has evacuated residents of 66 households 200 meters around the area and closed all the roads to it.

Experts believed that the subsidence was due to continuous stormy weather this winter which may have changed the geological structure underground.

Investigation into the accident is underway.

(Xinhua News Agency March 2, 2008)