Four of the dead were buried under collapsed buildings and were not found until Sunday, raising the death toll from four reported earlier, the ministry was quoted by the Xinhua news agency as saying.

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 State Seismologocial Bureau was quoted by Xinhua as saying.

Eight of those injured were in a serious condition, Xinhua said.

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 10,800 residential rooms were destroyed by the quakes and more than 3,000 livestock were killed or hurt, Xinhua said, citing the ministry of civil affairs. China usually records property damage in terms of rooms rather than buildings.

Sources from the Gansu provincial seismological bureau said 30 percent of the houses at the epicenter of the quakes had been severely damaged. Around 90 percent of the buildings in one village, Yaozhaizi, had collapsed, Xinhua said.

Damage was also caused to schools, grain warehouses, bridges, water and power supplies.

Cold weather in the disaster-hit areas were adding to the problems of quake victims. Temperatures in the area dropped to minus five to six degrees 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 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 quakes also damaged the dams of two reservoirs in Mingle county.

After cracks were found in dams, officials began slowly releasing water as they tried to repair the structures 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.

The two quake-hit counties are both located on an earthquake-prone belt in northwest China.

A powerful quake measuring 7.25 on the Richter scale struck Shandan county in 1954, claiming 50 lives and injuring more than 300.

TERRA.WIRE