The death toll from an expressway collision between a bus and a tanker in northwest China has risen to 36.

The death toll from an expressway collision between a bus and a tanker in northwest China has risen to 36, local police said Sunday.

The accident happened at around 2 a.m. in Yan'an, Shaanxi Province, when a double-decker sleeper bus crashed into a methanol-loaded tanker and caught fire.

Only three out of the 39 people on board the bus survived, but they all suffered injuries. The driver of the bus also died, police said.

State-run Xinhua news agency said that police are investigating the cause of the accident.

The State Council has sent an investigation team to Yan'an to look into the accident and oversee the rescue efforts, said officials with the State Administration of Work Safety.

The bus, which belongs to Hohhot Municipal Transport Group, was on its way from Hohhot, capital of Inner Mongolia Autonomous Region, to Xi'an, Shaanxi's capital.

However, the tanker, owned by Mengzhou No. 1 Transport Co., Ltd, was transporting methanol from Shaanxi-based Yulin Energy and Chemical Co., Ltd to the eastern province Shandong.