(CNN) At least 35 people died when a tour bus caught fire after ramming into a guardrail in China, state media reported. Two children are among the dead.

An additional 11 people were injured, four of them critically, and rushed to hospitals following the crash Sunday morning.

The blaze started after the bus crashed into a guardrail on a highway in the central province of Hunan. Leaking oil may have fueled the fire, police said.

The bus was carrying 55 people. The driver is in custody.