ALL BROKEN UP: Just stone and concrete, no reinforcement steel bars were seen in the collapsed bridge supports. -- PHOTO: REUTERS

Newspaper Beijing News quoted Mr Hou Jiaping as saying that the bridge across the Tuo river in the southern province of Hunan was mainly built of stone and concrete.

'No reinforced steel bars were seen in the collapsed bridge supports. It was like a knife cutting through tofu (beancurd),' he told the newspaper.

'Between the time people heard a loud sound and the full collapse there was only one minute,' he said. 'If it was built using cement and steel, it wouldn't have collapsed so quickly.'

Pictures in newspapers supported his comments. Sections of the bridge lay flat on the ground, lumps of rock bursting through the concrete and there were no steel bars to be seen.

An editorial in the official China Daily on Tuesday warned that thousands of the country's bridges were unsafe. 'If left unrepaired, these bridges may crumble at any time, wreaking economic havoc and possibly claiming human lives,' it said.

The government had already announced plans on Monday to fix or rebuild about 6,300 damaged or shoddily constructed bridges across the country by 2010.

Chinese State Councillor Hua Jianmian visited the collapsed bridge late on Tuesday and warned builders nationwide to learn from the disaster, which has rekindled concerns about shoddy work amid China's torrid economic expansion

Premier Wen Jiabao has called for a thorough investigation into the collapse, saying those responsible would be 'severely dealt with'.

Police detained two officials from the builder, the state-owned Hunan Road and Bridge Construction Co, Xinhua said.

More than 1,500 people were searching for about 30 missing people following Monday's disaster on the 320m-long bridge, which was on the verge of completion.

But they held out little hope of finding survivors and the health authorities were spraying disinfectant into the water to prevent the spread of disease.

'Because the bridge and pillars have all collapsed, it will be very difficult for rescuers to find or save people buried in the debris,' said deputy rescue director Luo Ming, adding they had to blast open the concrete to retrieve bodies.

Most parts of scenic Fenghuang county have had their water supplies cut off since the accident as the collapse of the bridge damaged water pipelines, it added.

REUTERS, ASSOCIATED PRESS