Battling bitingly cold weather and a lack of oxygen, rescue workers clawed with their bare hands through the rubble of homes and schools toppled by the 6.9 magnitude quake that hit Yushu county in Qinghai province on Wednesday.

Officials said medical teams and supplies such as tents and quilts were on their way to the zone, where doctors set up makeshift hospitals to treat victims of the deadliest quake in China in two years.

But thousands spent another night without shelter in freezing temperatures after the quake destroyed almost all the mudbrick and wooden houses in Jiegu, the local capital, and flattened schools.

“I lost my husband and I lost my house,” Gandan, a Jiegu resident, told AFP, her son and daughter at her side. All three were living in a tent with other people, with one bowl of barley to share.

“We don’t know what to do, we have no food,” she said, standing by the tent a stone’s throw from her collapsed mud and brick house.

China quake devastates stunned town

The number who perished rose to 760, including dozens of children, while 11,477 were injured, the official Xinhua news agency said, quoting rescue coordinators.

The death toll is expected to rise further, with 243 still buried, and local officials say they were short of medical supplies and large digging equipment.

“The rescue job in this disaster zone faces many difficulties,” said Miao Chonggang, of the China Earthquake Administration, which is coordinating more than 7,000 rescuers.

President Hu Jintao cut short a Latin American tour and Prime Minister Wen Jiabao postponed a trip to Southeast Asia.

Hu told a news conference in Brasilia the quake was “a huge calamity which resulted in big losses of human life”.

Chinese president calls quake ‘huge calamity’

Wen on Thursday visited the quake zone, an underdeveloped area of the Tibetan plateau known as the “Roof of the World”.

“The top priority is to save people. We will never give up even if there is only a slim hope,” Wen told a meeting at the quake-relief headquarters in Yushu, according to Xinhua.

Soldiers, police and firefighters used shovels, iron bars and bare hands to dig through the mangled piles of concrete and rubble from 15,000 toppled homes.

Foreign governments offered help as international aid officials warned that the priorities would be providing shelter, medical aid, food and water and ensuring sanitation to prevent the spread of disease.

Meanwhile tens of thousands of Internet users have been showing their solidarity with the quake victims by posting virtual flowers in online “mourning halls” and donating to appeals, Xinhua said.

Jiegu lies around 800 kilometres (500 miles) by road from the provincial capital Xining, about 4,000 metres above sea level, meaning rescue workers from outside the region struggled to cope with the lack of oxygen.

The government said electricity and phone links had been restored to dozens of towns but the difficult terrain, including deep canyons, and the bitter cold and remoteness of the area were hampering rescue efforts.

Dazed survivors told harrowing stories of loved ones crushed under their homes.

“There are 10 people in my family and only four of us escaped. One of my relatives died. All the others are buried under the rubble,” Samdrup Gyatso, 17, told Xinhua after his two-storey home crumbled.

Facts on China quake zone

Among the dead were at least 66 pupils and 10 teachers, Xinhua said, quoting local authorities, as grieving parents waited for news near the ruins of the schools, where discarded school books and clothes lay.

Xinhua said a baby boy had been born in a tent near the epicentre shortly after the quake.

“It must be the first life that came to the world after the disaster,” Huang Changmei, a doctor, told the agency.

“The baby brought hope to the ruined place.”

The devastation was reminiscent of the huge quake in May 2008 in Sichuan province, where thousands of children were among 87,000 deaths when their shoddily-constructed schools collapsed.

Schoolbooks strewn in China quake rubble as children perish

Xu Mei, of the education ministry, denied a media report that around 200 children had been buried in the ruins of a primary school in Wednesday’s quake.

In Beijing, Zou Ming, the head of the government’s disaster relief department, said nearly 40,000 tents, 120,000 articles of clothing, 120,000 quilts and food were being dispatched.