Bodies are found in rubble that was once a school

Rain turned the playground to mud as rescuers dragged the bodies of hundreds of schoolchildren out of the wreckage of the Juyuan Middle School, in earthquake-shattered Sichuan province, leaving the corpses to be identified by their grieving parents in a makeshift mortuary in the basketball court.

Each corpse claimed was marked with a barrage of firecrackers, a traditional way of sending the souls of the dead children home and warding off evil spirits. Wave after wave of aftershocks played havoc with relief efforts across the stricken earthquake zone, where the death toll has soared to more than 12,000.

Rescuers were still trying to get to remote areas and there were fears that the death toll could double when emergency teams are able to assess fully the damage to Wenchuan county, a city of 120,000 which lies right above the epicentre of the earthquake at the foothills of the Tibetan plateau. Dense cloud cover and driving rain made mobilising troops in Wenchuan difficult but the prognosis is poor.

Driving west from Chongqing to Chengdu, the roads were full of trucks bearing telecommunications and medical equipment for the affected areas. There were long queues outside petrol stations. About 2,000 tourists were travelling through the region at the time of the quake, including 15 Britons and 12 Americans on a panda-watching tour.

China has mobilised more than 50,000 soldiers to help victims of the country's worst disaster since the Tangshan earthquake in 1976, which left about 250,000 dead (although Chairman Mao Zedong muzzled reporting of the true toll). Reporting on the current crisis has been candid, reflecting growing openness in media coverage of disasters, which started with the Sars epidemic in 2003 and also allowed coverage of a series of mining disasters in subsequent years.

Half-a-million houses have been flattened by the earthquake, and the streets of the worst-affected towns are strewn with electrical cables and other debris. Before the clean-up operation can even begin, damage limitation needs to be completed but driving rain is making progress difficult.

According to state television, the official death toll is about 12,000, but that is expected to rise dramatically with at least 10,000 people reportedly found buried in Mianzhu city alone.

At the Juyuan Middle School, everyone spoke of what had happened to the xiao pengyoumen, which translates as "little friends", and there was a strong sense of bewilderment as people tried to come to terms with the earthquake, which struck at around 2.30pm when the students were in afternoon session.

The outside walls of the school slid away as the ground shook, turning the b uilding into a concrete tomb for the estimated 900 children in the school on the day. Support walls left standing have blackboards on them, with the lessons of the day still written on them. "The building collapsed so suddenly, the little friends didn't stand a chance. They didn't have a chance at all," said one resident, who gave his surname as Li, a day after the earthquake shook the life out of Dujiangyan city, about 30 miles from the epicentre of the quake.

The Chinese premier, Wen Jiabao, said during a visit to the disaster relief headquarters in Dujiangyan: "Rescue teams of soldiers and armed police officers are going all out to reach the worst-hit regions and many have already started rescuing trapped people."

One of the barrages of firecrackers confirmed the death of Li Chunyan, 16. Her mother told of how she scrabbled desperately to find her only child. "When the earthquake happened, within two minutes we all rushed down here to dig," she said. "I wanted to dig her out with my own two hands. All the families did. Li Chunyan's grandfather, aunts, uncles, we all dug until our fingers were sore. We are quicker than the machines. The machines didn't do it right."

The death of a child is always bitter, but there is an extra edge of horror for many of the parents in Dujiangyuan. The one-child policy means many of the dead students were only children, and the fact that they were teenagers means that, for many families, there will be no more children. Li Chunyan's grandfather refused to leave a tent erected near the school. "I'm going to wait for her here," he said. "I'm not going to accept that she's not coming back."

Juyuan Middle School had around 1,500 students, aged between 12 and 16, although some of the little bundled bodies in the field mortuary looked a lot younger. Behind the grimy flaps of the tent, where perhaps 20 bodies lay, one mother shook the wrist of the muddy grey body of her son, trying to wake him. He wore an Adidas sweatshirt and a baggy pair of jeans and looked to be about 13 years old.

The response from the authorities was quick – China is efficient in dealing with natural disasters and there is a lot of manpower around to help with the digging.

A soldier, who gave only his surname Zhang, had been working flat out since an hour or two after the earthquake.

"We're still digging the deeper section," he said, before setting off to continue his work.

Heads turned for the latest volley of firecrackers, then got back to the business in hand.