MIANYANG, China - With survivors still emerging from the rubble Saturday nearly 115 hours after disaster struck, rescue teams waged an increasingly desperate battle to find victims of China's earthquake which has claimed an estimated 50,000 lives.

With towns and villages reduced to a mass of twisted metal and concrete, recovery teams used sniffer dogs and cutting equipment to try and find victims trapped under buildings, five days after the quake struck the southwest.

A German tourist was pulled out of the wreckage after being buried for 114 hours, state-run Xinhua news agency said Saturday.

The confirmed number of people killed was 22,069 late Friday, with officials in worst-hit Sichuan province saying another 14,000 remained buried.

But as foreign aid teams joined the rescue effort, search and rescue workers remained resolute in their mission to find survivors.

"Giving up is excluded from our dictionary," a rescue worker was quoted as saying by Xinhua, after a child was pulled alive Friday from a ruined school in the town of Beichuan.

"The possibility is very great that we can rescue the buried," the rescuer said, five days after the 7.9 magnitude quake struck Sichuan province.

Chinese Premier Wen Jiabao, who state media has reported was personally leading rescue efforts, said: "Where there is a beam of hope, we will spare no efforts to save the trapped."

But with another 4.8 million people left homeless by the disaster, according to Sichuan officials, there is also much anger at how towns and cities could be felled in a matter of minutes.

Close to 7,000 schools -- a disproportionately high number of buildings -- were destroyed in Sichuan province by the quake, which struck in the afternoon when many children were in class or taking their daily naps.

"Look at the building materials they used," said one resident in the rural
community of Juyuan where the middle school was destroyed.

"The cement wasn't mixed with water in the right proportion. There are not enough steel beams. The sand isn't clean," the resident said, blaming poor workmanship for the four-storey school's collapse. Hundreds of children were killed while nearby buildings remained standing.

People in Juyuan said the local government used educational funds allocated to them to build the school, and awarded the project to a contractor but someone along the way had decided to cut corners.

"The local officials get money from above, and then they take part of it for themselves," said Liu Gan, a 25-year-old worker, sticking his right hand in his pocket in a telling gesture.

"The whole world knows local officials take money for themselves. Only the central government doesn't," said Liu, who himself attended the school.

Housing Minister Jiang Weixin on Friday announced a probe had been launched into whether shoddy work linked to corruption was to blame for the large number of schools toppled by the quake.

"Unfortunately we can't rule out that there may have been situations where people scrimped on workmanship and stinted on materials during the construction process and if so we will deal with any such problems strictly after an investigation," Jiang told a press conference in Beijing.

China's state media has already suggested that developers across the nation may have tried to maximise profits by using inferior materials or cutting back on necessary work while paying off corrupt officials to turn a blind eye.

With time running out for survivors the United Nations has released seven million dollars in aid for China following the quake, UN spokeswoman Michele Montas said Friday.

The money, which will be taken from the organization's Central Emergency Response Fund (CERF), will be used by different UN agencies and programmes to help China meet urgent humanitarian needs.

"The United Nations stands ready to provide further support, as required, to the government of China in its efforts to respond to the humanitarian needs caused by the disaster," Montas said. - AFP/ir