Thousands of rescuers are fighting to thwart a rising death toll as they search earthquake-shattered villages in southwest China for survivors.
Rescue teams battled landslides and collapsed roads to reach isolated parts of Sichuan province on the edge of the Tibetan Plateau, in images aired on state broadcaster CCTV.
At least 180 people have so far been confirmed dead, with 6,000 injured in Saturday's 6.6 magnitude quake.
Soldiers searched through the night and day for survivors in villages where houses had been destroyed and treated some of the injured.
China's new Premier Li Keqiang has rushed to the disaster zone and was shown by CCTV eating breakfast in a tent.
"The rescue effort is our first duty," he told state media.
Xinhua news agency said more than 17,000 Chinese soldiers, pilots and police had joined the rescue mission and five drones were sent to capture aerial images.
A military vehicle carrying 17 troops headed for the quake area plummeted over a cliff on Saturday, killing one soldier and injuring seven others.
Al Jazeera’s Robert McBride, reporting from Hong Kong, said the suddenness of the earthquake had contrasted with the 2008 one in the same province, which left more than 90,000 people dead or missing.
"People are now watching to see how the new leadership is dealing with this," McBride said.
"This their first test of how they deal this natural disaster."
The rescue operation was hampered by huge queues of traffic, some stretching back for 20km, that clogged roads into the disaster zone.
| Primer Li Keqiang has rejected an offer from Japan, saying foreign help is not needed at this stage [AFP]
"We really want to go in and help people, but instead we are waiting in traffic," one relief official said in his car.
Boulders the size of cars littered streets in Lushan county, the epicentre of the earthquake.
More than 1,100 aftershocks have followed since the quake struck Sichuan province on Saturday morning.
Chinese seismologists registered the tremor at 7.0 magnitude while the US Geological Survey gave it as 6.6.
Firefighters helped by sniffer dogs pulled 91 people alive from the rubble, Xinhua said, citing the Ministry of Public Security.
A steady stream of ambulances continued to arrive at Lushan People's Hospital on Sunday.
Most survivors were taken to tents erected in the grounds surrounding the hospital, where doctors treated the wounded.
A 68-year-old woman with a broken arm spoke of the terror she experienced when the earthquake struck.
"It was as if the mountain was alive," she told the AFP news agency. "Now I have no home to go, so I don't know what I am going to do."
The earthquake cut off power and water supplies to much of the area, with Longquan villager Sot Yang Yiyun among the many affected.
"Now we don't have drinking water and power," Sot said.
"We must wait for the government to come and help us out. Also we want to call for help from other parts of the country."
Earthquake-prone Japan, which has been mired in tension with China over a high-seas territorial dispute, offered any help that was required.
"Japan is ready to offer its maximum support," Prime Minister Shinzo Abe said in a message to Chinese President Xi Jinping and Premier Li, according to Japan's foreign ministry.
China responded that overseas help was not needed but it would contact Tokyo if the situation changed, the ministry said.