Chinese rescue teams have reached some of the most remote areas of Sichuan province hit by Saturday's powerful earthquake, state media report.
The rescuers have been travelling on foot into Baoxing County because of the damage to roads in the isolated region.
Communication networks are still disrupted, so the extent of the destruction is still unclear.
State media say 207 people are dead or missing after the quake, and 11,500 are injured, 960 of them seriously.
More than 1,300 aftershocks have been felt in the area since the 6.6 magnitude quake struck at 08:02 local time (00:02 GMT) on Saturday, raising fears of possible landslides.
Long traffic queues have also held up efforts to get aid supplies and volunteers to the affected areas.
Premier Li Keqiang is in Ya'an, the closest city to the epicentre, overseeing relief efforts, and told reporters that saving lives was the most important thing.
The BBC's John Sudworth in Ya'an says dozens of injured people are still being treated in a triage centre outside the main hospital.
Some villages close to the epicentre in Lushan and Baoxing counties were left in ruins.
One survivor, Yang Shanqing, said he had lost his family in the disaster.
"I tried to call my brother but could not get through. I ran back to the village and was told at the entrance of the village that my brother's house had collapsed," he said.
"I rushed here only to see a crowd of people trying to grab the family out of the ruins, but they failed."
At the Vatican, Pope Francis in his weekly address said his thoughts were with the people of China.
'Waiting in traffic'
China has received offers of help from countries including Japan, with which it is currently embroiled in a territorial dispute over an island grouping in the East China Sea.
Beijing said overseas help was not needed at the moment, but added that it would contact Tokyo if that changed.
Chen Yong, the vice-director of the Ya'an city government earthquake response office, said the death toll may not rise much more.
"We understand the situation in most areas. Most of the casualties have been reported," he said.
"In some remote mountain areas, it is possible that we don't fully understand the situation."
Correspondents say the hill villages, where farmers grow rice, vegetables and corn on terraced plots, were hit the hardest.
On Sunday, ambulances, fire engines and military lorries piled high with supplies were waiting in long lines along blocked roads in the province.
Kevin Xia of the Red Cross said: "Supplies have had difficulty getting into the region because of the traffic jams. Most of our supplies are still on the way."
Another relief official told Reuters: "We really want to go in and help people, but instead we are waiting in traffic."
Our correspondent says the authorities have stopped issuing permits for journalists to enter the region, saying they are adding to the congestion.
In Longmen village in Lushan county nearly all the buildings were destroyed, officials said.
Rescuers had to dynamite boulders that had fallen across some roads, while overnight rain slowed rescue work.
A military vehicle carrying 17 soldiers came off the road, killing one soldier and injuring others.
Many thousands of people spent the night in tents or cars, unable to return home or too afraid to go back because of the aftershocks.
Sichuan province was devastated by a massive quake five years ago that claimed tens of thousands of lives and left five million without homes.
Many of the collapsed buildings were schools and nurseries, leading to widespread criticism of local government's planning policies.
But Mr Chen said that this had not happened this time.
"The Chinese government has put a lot of money into building schools and hospitals. I can guarantee that no schools collapsed," he said.