HONG KONG — A double-decker sleeper bus plowed into the back of a tanker carrying flammable methanol on an expressway in Yan’an in northwestern China’s Shaanxi Province on Sunday morning, setting off a fire that killed 36 people, including the bus driver, and injured three, the state-controlled media said.

The crash was the deadliest bus accident in China since July of last year, when luggage that may have contained fuel ignited aboard an intercity bus, killing 41 people.

Two drivers of the tanker survived the crash on Sunday and were detained for questioning, the official Xinhua news agency said.