BEIJING (AFP) -- At least 36 people died in a fiery collision between a methanol tanker and a double-decker sleeper bus on Sunday in China’s worst traffic accident in more than a year.

Both vehicles caught fire and only three of the 39 people onboard the bus survived the motorway crash, which occurred around 2:00 a.m., Xinhua news agency reported.

A total of 36 bodies were pulled from the debris and three people were taken to hospital.

The accident was the worst in China since a fire on an overcrowded sleeper bus carrying flammable materials killed 41 passengers in central China in July last year, according to the country’s work safety watchdog.

Details of Sunday’s crash -- which happened 200 meters from a motorway service station at Yanan city in northern Shaanxi province -- were still unclear.

Yue Jiuxiang, a local traffic police official in charge of the rescue operation, said most of the passengers were asleep at the time of the crash.

“Soon after the collision, the bus was engulfed by flames,” he told state-broadcaster China Central Television.

“The front part of the bus was seriously damaged. Also most of the passengers were sleeping. This is why so many people died.”

Yue said the bus was en route from Baotou in Inner Mongolia to the Shaanxi provincial capital Xian when the collision occurred.

Police were investigating the cause of the accident which happened on the Baotou-Maoming Expressway, which spans the length of China from the northern city of Baotou to the southern province of Guangdong.