The Chinese military is air-dropping food and medicine to earthquake survivors in remote mountain villages of Sichuan province, but time is running out for thousands buried under the rubble and mud of collapsed buildings, homes and schools.

China raised the official death toll again Wednesday to nearly 15,000. Authorities expect that number to go up as rescue crews arrive at the hardest-hit areas and begin digging through the rubble.

Officials estimate that an additional 40,000 people are either buried or missing.

As help arrived in some of the hardest-to-reach areas today, some victims were being pulled out alive.

The official Xinhua news agency says seven military helicopters have delivered supplies to Wenchuan county, the epicenter of the 7.9 magnitude quake, and several surrounding counties.

A local government official told Xinhua that only 2,300 of 10,000 residents in the southwestern town of Yingxiu survived the earthquake. The official says rescuers found the situation in Yingxiu worse than expected, with traffic cut off and children buried in debris.

The Sichuan provincial government says a hydropower plant located between the hard-hit areas of Dujiangyan City and Wenchuan County has been shut down. Local officials tell state-media that there are severe cracks in the dam, Zipingpu Hydropower Station, and that the plant and its buildings have collapsed and sunk.

Wenchuan county also is home to the Wolong Nature Reserve, China's largest breeding center for giant pandas.

A spokesperson for the State Council's Taiwan Affairs Office, Wang Yi, told reporters they finally made contact with reserve officials, who assured him that two pandas Beijing wants to send to Taiwan are safe.

More than 50,000 troops have been sent to assist with relief work in quake-affected areas, but China has said conditions are not right for international teams to come in and help.

Pope Benedict has called for prayers for victims of the deadly earthquake. Speaking during his weekly audience in St. Peter's Square, Wednesday, the Pope said his thoughts are with the people of Sichuan and surrounding areas.

Some information for this report was provided by AFP, AP and Reuters.