Relatives cried, monks prayed, and rescuers clapped Friday as a teenage girl emerged alive after more than two days under the flattened ruins of a hotel in quake-stricken west China.

The 13-year-old was immediately carried away to a medical center in Gyegu town at about 2 p.m. as delighted rescuers congratulated each other.

However, the excitement after the six-hour dig was short-lived as they suppressed their fatigue and the nausea of altitude sickness to return to work.

The young life saved was also an acute reminder that the time for survival is slipping away.

Thousands of rescuers know they are fighting the clock to pull more people from the debris in the remote northwest China town as the optimum survival time is just 72 hours.

But the high altitude, thin air, freezing temperatures and electricity shortages are hampering their efforts.

By Friday at least two dozen trained rescuers had stood down due to altitude sickness, said police and military sources participating in the rescue.

The 7.1-magnitude quake hit the Tibetan Autonomous Prefecture of Yushu in southern Qinghai Province early Wednesday. By Friday, at least 791 people were dead, 11,486 were injured, and 294 were missing.

The quake flattened 15,000 residential buildings in Gyegu town near the epicenter and many people are believed to still be trapped under the rubble.

The impoverished town sits about 4,000 meters above sea level. Conditions are especially hard for the injured who are yet to be reached.

A cry for life

Tibetan woman Jang La, 43, told Xinhua at a medical tent that she was buried for more than 50 hours and had no access to food and water.

"I thought no one would manage to save us and I lost hope, but as I yelled and yelled for help, they came and rescued us," Jang La said.

Medical attendant Jiao Xiaojie said Jang La's hips were crushed under falling masonry, but her condition appeared stable.

Jiao said he had treated four or five people who were rescued Friday morning.

A string of survivors on Friday were sent to the emergency tents for treatment at Gyegu. Trucks carrying the sick and the injured zigzagged out of the mountainous region to the provincial capital of Xining.

"The first 72 hours offers the best chance of survival after such a calamity strikes," said Xi Mei, a medical attendant with the China International Rescue Medical Team.

But time is running out.

Fu Yong, head of a group of rescuers from Lanzhou, Gansu Province, said they had pulled out six bodies, but no survivors.

"The possibility of survival is getting slim, but we are still looking for miracles," he said.

Wang Qinlin, head of a group of police rescuers, said his men, armed with life detectors, had spread out to remote villages, small alleys in and around Gyegu to find survivors.

"We are fighting the clock and we will not give up on the smallest chance," he said. "Once a sign of life is detected, we call in the back-up team and start digging."