Beijing, Nov 2 (IANS): A fistfight between a passenger and a bus driver was found to have caused a bus to plunge into the Yangtze river in China's Chongqing earlier this week killing 13 people, authorities said on Friday.

Thirteen bodies have been retrieved from the river in Wanzhou district, and have all been identified. Two remain missing, Xinhua news agency said.

The police managed to restore data from the bus tachograph retrieved from the river on Wednesday as well as the surveillance video from inside the bus.

The investigation showed that the female passenger planned to get off at a certain stop, but the bus had to make a detour and would not arrive there due to road maintenance.

The driver told passengers to get off at an earlier stop. However, the female passenger did not get off and later asked the driver to stop the bus when she realised she missed her destination.

The driver refused as there was no bus stop in view, and an argument broke out, that soon turned into a fistfight.

The driver's right hand came off the steering wheel during the altercation, which led to the steering wheel turning sharply to the left, the police said.

The bus then veered onto the wrong side of the road and collided into an oncoming car before breaking through fencing and flying off a bridge over the Yangtze river on Sunday.

Rescuers on Wednesday night pulled the bus from the river.