A bus burst into flames when it collided with a guardrail on a motorway in central China on Saturday, killing 35 people, state-run media reported.
The accident in Hunan province's Yizhang county also sent 21 people to local hospitals.
There were 56 people on board at the time crash, Xinhua news agency reported.
An oil leak was suspected of causing the vehicle to catch fire, the report said.
No other vehicles were involved in the collision.
Local police said the 41-year-old driver of the bus had been taken for questioning. Why the bus had crashed into the guardrail was not immediately clear.
Bus accidents are common in China, where drivers often work long hours, vehicles are not regularly vetted and many roads are in bad condition.