At least six people were killed and 50 feared trapped when a bridge collapsed in Rajasthan, police said on Friday. The accident occurred Thursday evening during the construction of the bridge over the Chambal river, police said. Soldiers joined in rescue operations which continued overnight at the site in Kota city, some 240 kilometres south of state capital Jaipur. Witnesses said the accident happened when about 100 labourers were working in the Kunhadi area. We have recovered six bodies till now, Kota police official Laxman Goud said over the telephone. Many workers were rescued and eight men who sustained serious injuries were being treated at local hospitals. We estimate that nearly 50 workers are still trapped. The death toll is sure to rise since there is little chance we will find survivors after the rubble is cleared, Mr. Goud said. Rajasthan Security Minister Shanti Dhariwal accused Gammon India and South Korean firm Hyundai, two companies jointly building the 50-metre bridge, of criminal negligence. Local police launched an investigation into the incident and registered a case against the companies. They were questioning two engineers from the South Korean firm.