China ramped up its massive military rescue effort in the quake-hit southwest Thursday where more than 40,000 people lay dead or buried under rubble and rescue teams fought to save the living.
Premier Wen Jiabao ordered another 30,000 troops and 90 helicopters to the disaster zone to reinforce the search-and-rescue operation, and the military was planning the first large-scale air drops of key supplies.
The full scale of the devastation is only now beginning to emerge as teams hike into the remote epicentre of Monday's powerful 7.9-magnitude earthquake, which flattened whole towns causing untold loss of life.
In Yingxiu, a town of about 10,000 people where the epicentre of the quake struck, most of the buildings had collapsed and a desperate relief effort was underway for the survivors, an AFP reporter witnessed Thursday.
"I want to go home. I miss my mum and dad," said a 21-year-old girl from a nearby town who was visiting her boyfriend here when the quake hit.
A new threat has also emerged with rivers swelling to dangerous highs after landslides and authorities reporting cracks in a key dam near Dujiangyan, less than 50 kilometres (30 miles) from the quake's epicentre.
"We must use all our forces, and save lives at whatever costs," Wen told a meeting late Wednesday at the quake relief headquarters in Dujiangyan.
"Life is the most precious thing, we must be amenable to the people and to history."
China's state-run Xinhua news agency said large-scale airdrops would begin later Thursday, flying more than 50,000 food packets and tens of thousands of items of clothing and blankets into the areas worst hit.
The military is also deploying 30 more transport aircraft to ferry rescuers and supplies across Sichuan province, and an AFP reporter saw dozens of army trucks heading north to the disaster zone from the provincial capital Chengdu.
Helicopters are especially vital to the relief effort as much of the quake area consists of mountain villages and towns cut off by huge landslides.
Xinhua said the total number of troops, armed police and regular police now involved in the operation exceeded 116,000.
The destruction around the epicentre in remote Wenchuan county is massive, with whole mountainsides sheared off, highways ripped apart and building after building levelled.
Authorities have so far reported nearly 15,000 confirmed deaths in Sichuan province, but that is expected to soar dramatically because of the huge number of people lying buried under broken homes, schools and factories.
At least 7,700 people were feared dead Yingxiu alone.
Sichuan's vice governor said nearly 26,000 people were buried, while Xinhua late Wednesday reported 30,000 missing or out of reach in the city of Shifeng alone.
Far beyond the numbers, however, is the human tragedy behind China's worst quake in a generation as rescue teams claw through twisted metal and concrete, dragging out bodies and bloodied survivors alike.
They were looking for people like He Xinghao, 15, whose lifeless body was pulled from the debris of a school close to the epicentre.
Like many other Chinese of his age, strict population policies had made him an only child, and he was showered with affection by his family.
"He was such a good and well-behaved boy. He always did his homework," said his aunt, Ge Mi, as fresh tears flowed from her reddened eyes.
It was a scene repeated across Sichuan -- a province often better known to foreigners for its endangered giant pandas.
Many thousands of others across Sichuan are homeless, living and sleeping out in the open under makeshift shacks.
State media reported that rescue teams and villagers in Sichuan's Beichuan county were temporarily evacuated to higher ground amid fears a blocked river could burst a natural dam and flood downstream.
Xinhua also quoted the water resources ministry saying cracks appeared on the surface of a large dam near Dujiangyan and the city "would be swamped" if major problems emerged, but officials later assured it was safe.
World powers including the United States, European Union and United Nations have offered money and expertise, and Pope Benedict XVI called for prayers to be said.
However, China has rebuffed most offers of sniffer dogs and foreign search and rescue experts -- accepting only a Japanese team -- saying conditions were "not yet ripe."