BEIJING (Reuters) - Police in southwestern China have detained four suspects following the collapse of a pedestrian bridge which killed 40 last week, state media said on Wednesday. The China Daily said two of the suspects had been forced to leave their jobs, but did not specify their involvement in the January 4 bridge collapse in Qijiang county outside Chongqing. Shoddy construction and structural defects in the three-year-old bridge were blamed for the collapse, which happened as paramilitary troops were jogging across the span. Rescue workers have recovered the bodies of 18 para-military police and 22 civilians, including a seven-month-old child from the water below the 102-metre steel and concrete Rainbow Bridge. A further 14 people were injured. Following the accident, local authorities ordered a halt to construction of a similar bridge just 1.5 kilometres from the collapse site. Inspectors said the second bridge was also poorly made and had serious structural problems. They added that the construction company had not applied for permission to build it. At a national work conference on Tuesday, Minister of Construction Yu Zhengsheng urged an improvement in the quality of the country`s construction projects. Chinese public works projects have been plagued by inferior building work, often the result of corruption or cuting corners to save money. The number of complaints about shoddy construction has risen by more than 50 percent since 1997, the paper said.