The quakes, measuring 6.1 and 5.8 on the Richter scale, jolted areas between Minle and Shandan counties of Gansu province's Zhangye city at 8:41 pm (1241 GMT) and 8:48 pm (1248 GMT) Saturday, the bureau said according to the Xinhua news agency.

Eight of the 25 people were seriously wounded while the others suffered minor injuries, Xinhua said.

The People's Daily website, however, said 29 people were injured and four others buried in rubble have not been rescued.

An official told AFP the final tally was not yet available.

"Approximately four townships have been affected. I don't know exactly how many people have suffered," said the official from the Zhangye city seismological bureau.

Most residents in the area are farmers or herdsmen.

More than 10,000 residential rooms have been destroyed by the quakes, Xinhua said citing the ministry of civil affairs.

Sources from the Gansu provincial seismological bureau said 30 percent of the houses in the epicenters have been severely damaged, while 90 percent of the buildings in one village, Yaozhaizi, have collapsed, Xinhua said.

Cold weather in the disaster-hit areas are adding to the problems of quake victims. Temperatures in the area dropped to five to six degrees below zero Celsius (23 degrees to 21 degrees Fahrenheit) and it had snowed in the area a few days ago, Xinhua said.

The ministry has sent 2,000 cotton-padded tents to quake-hit regions.

Zhangye's mayor Tian Baozhong said many officials, locally-based People's Liberation Army soldiers and the armed police were searching for injured people while trying to recover food from collapsed homes, according to the People's Daily.

The quake damaged a reservoir in Mingle county, which stored 20 million cubic meters of water, the Daily quoted another official as saying.

After cracks were found in the reservoir's gate, officials began slowly releasing water as they tried to repair the structure to prevent a major accident.

The epicenters of the quakes are about 500 kilometers (320 miles) from Lanzhou, the capital of Gansu province.

The provincial government and the State Seismological Bureau have sent a task force to the area, the report said.

Chinese Premier Wen Jiabao has asked the ministry to respond in a quick and comprehensive manner to help the victims, Xinhua said.

TERRA.WIRE