Rescue boats were combing the middle reaches of the Yangtze River searching for survivors of a passenger ship that sank after colliding with a cargo boat on the river above the massive Three Gorges Dam. The accident happened just before 8:00 am near Fuling city, 270 kilometers (167 miles) from the dam, but on the upper end of a huge reservoir now being formed by the hydroelectric project, local officials said Thursday. "At present we don't know how many people were on the boat because between Zhenan township and Fuling city the boat stopped to pick up and let off passengers five times," Liu Zhongguo, an official at the Fuling city government said. "It will take at least until tomorrow midday to know because we have to go to each stop and ask local villagers who was on the boat." Xinhua news agency said that so far three bodies had been recovered. China Central Television (CCTV) in an unsourced report said that only 35 people were aboard the passenger ship when it crashed, while the China News Service said at least 100 were on board. "Exact number of passengers aboard the passenger liner remains unclear, but local people said they should include students and vegetable sellers going to market," Xinhua said. The accident occurred when the Fuzhou No. 10 passenger boat, owned by the Yangtze River Three Gorges Tranport Shipping Company Ltd., struck a cargo boat owned by the Fuling Jianglong Shipping Company as it headed downstream, it said. Twelve people had been rescued from the passenger ship which sank after the collision, while the cargo boat remained afloat, reports said. Two local hospitals told AFP that 10 injured had so far been admitted. "We have received nine people from the accident so far," said Dr. Zhang Yi from the Lingshi Hospital. "They are all in a stable condition. I heard around 13 people have been rescued." The Central Hospital of Fuling city said it had so far seen one injured person. "She told me she swam to the shore," said a doctor who declined to be named. Local officials said the area was shrouded in thick fog at the time of the collision and the boats should not have been on the river. "At the time of the collision there was heavy fog. Both boats were violating regulations because according to regulations boats cannot leave port in heavy fog," an official surnamed Cui from the Changjiang Chongqing navigational channel bureau said. An official surnamed Wang from the Fuling Maritime Bureau supervision section said the Fuzhou No. 10 was capable of carrying 350 people, but was unable to say how many were on board Thursday. The mayor of Chongqing city was at the scene directing rescue operations, reports said. A member of a local TV station, who did not want to be named, told AFP that editors had ordered that the incident not be reported. The ruling Communist Party keeps a tight rein over China's media, regularly muzzling it and demanding it steer clear of controversial issues. The accident could be potentially embarrassing to the central government if the mishap was somehow related to the controversial 25 billion dollar dam, the world's largest hydroelectric station. On June 1, the giant sluice gates on the 185-meter (610-feet) Three Gorges Dam were shut as the resevoir, which will eventually stretch all the way up to Fuling, began storing up water. Earlier this week the giant ship lock was opened for a trial run and was formally expected to open as soon as Friday. Traffic on the river has been blocked for nearly 70 days because of the dam, with boats lining up earlier this week eager to resume the normal busy traffic on the river, China's longest. **PHOTO CAPTION*** Barges make their way along the swollen Yangtze river. Scores of passengers were missing after a passenger ship and a cargo vessel collided in heavy fog on the Yangtze River.(AFP/File)