Chinese rescue workers are blasting to clear mounds of rock blocking roads as emergency teams try to reach isolated earthquake-hit towns in the south-western province of Sichuan.
The death toll in China's worst earthquake in three years stands at more than 200, with almost 12,000 people injured.
Ongoing aftershocks are causing major landslides in the earthquake disaster zone, and falling rocks continue to block entry into some of the worst hit areas.
Most of the deaths have been concentrated in Lushan, a short drive up the valley from the city of Ya'an, but rescuers' progress has been hampered by the narrowness of the road and landslides, as well as government controls restricting access to avoid traffic jams.
Rescue teams are queuing up and waiting to reach isolated towns and some communities are still only accessible by helicopter.
Firefighters helped by sniffer dogs have pulled 91 people alive from the rubble.
"The Lushan county centre is getting back to normal, but the need is still considerable in terms of shelter and materials," said Kevin Xia of the International Federation of Red Cross and Red Crescent Societies.
"Supplies have had difficulty getting into the region because of the traffic jams. Most of our supplies are still on the way."
In Ya'an, relief workers from across China expressed frustration with gaining access to Lushan and the villages beyond, up in the mountains.
"We're in a hurry. There are people that need help and we have supplies in the back [of the car]," said one man from the Shandong Province Earthquake Emergency Response Team.
Thousands of people are being treated in temporary trauma hospitals which have been set up to handle the waves of injured.
Doctors and nurses are tending to people in the open or under tents in the grounds of the main hospital, surrounded by shattered glass, plaster and concrete.
Water and electricity have been cut off by the quake, but the spring weather is warm.
The ABC visited a mobile trauma unit where rescued patients moaned quietly as concerned relatives sat by their bedsides holding hands and offering comfort.
One man was sitting with his recovering 80-year-old mother and 90-year-old father.
"When the quake hit I was downstairs," he said.
"I dashed upstairs to rescue my young son, but after I did I noticed my parents had been crushed by bricks, so I carried them both out."
Many of the injured people have broken bones and skull fractures.
Premier Li Keqiang flew into the disaster zone by helicopter to comfort the injured and displaced, chatting to rescuers and clambering over rubble.
"Treat and heal your wounds with peace of mind," the Chinese newsagency Xinhua quoted Mr Li as telling patients at a hospital. "The government will take care of all the costs for those severely wounded."
Chen Yong, the vice director of the Ya'an city government earthquake response office, said the death toll was unlikely to rise dramatically.
Already poor, many of the earthquake victims said the government was their only hope.
Cao Bangying, 36, whose family had set up mattresses and makeshift cots under a dump truck, said her house had been destroyed.
"Being without a home while having a child of this age is difficult," Cao said, cradling her nine-month-old baby. "We can only rely on the government to help us."
At least 1,700 aftershocks have followed since the quake struck Saturday morning. Chinese seismologists registered the tremor at 7.0 magnitude while the US Geological Survey gave it as 6.6.
More than 17,000 Chinese soldiers and police have joined the rescue mission and five drones were sent to capture aerial images, Xinhua said, as well as aircraft carrying out rescue and relief work.