Two traffic accidents claimed the lives of 47 people on Sunday, renewing concerns over the safety of overnight buses and vans carrying children.

Bodies are removed from a bus on Sunday after it hit the rear of a tanker in Yan'an, Shaanxi province. [Photo / China Daily]

Thirty-six people were killed early on Sunday morning after a bus rammed into a tanker carrying methanol, a highly flammable liquid, and caught fire on a highway in Northwest China's Shaanxi province. Three people were injured, two of them seriously.

And an accident in Sichuan province, in broad daylight on Sunday afternoon, killed 11 people when a van, with 12 people, including three children, collided into the rear of a stationary truck.

The bus, carrying 39 people, hit the tanker at about 2:40 am near the city of Yan'an on the Baotou-Maoming Highway, according to a statement released by the Yan'an government.

The accident resulted in the tanker catching fire and the flames engulfed the bus, killing 36 people, the statement said.

Two of the survivors, a 42-year-old man surnamed Zhang from Hohhot in the Inner Mongolia autonomous region, and a 27-year-old woman from Sichuan province, were seriously injured and were being treated for burns in a hospital in Yan'an.

Pictures of the accident site showed that the back of the tanker was firmly lodged in the bus, indicating that the bus had crashed into it at speed.

Police detained both drivers of the tanker, who were not injured in the accident.

The State Council has dispatched an investigation team, headed by a deputy chief of the State Administration of Work Safety and a vice-minister of public security, to investigate the accident.

Yue Jiuxiang, a Yan'an firefighter, said some of the bodies were difficult to identify, and the local government will carry out DNA tests.

The overnight, or sleeper bus, run by a Hohhot transport company, was en route to Xi'an, Shaanxi province. The tanker, from Yulin, Shaanxi province, was on its way to Shandong province.

Neither vehicle was overloaded, the statement said.

An official from the publicity department of the State Administration of Work Safety, said driver fatigue was often blamed for accidents involving long-distance vehicles.

The cause of the accident is under investigation, the official said.

Accidents: More than 5,000 routes across the country

This is not the first deadly accident involving sleeper buses.

In July 2011, a fire on an bus in Henan province resulted in the death of 41 people. The bus had been en route from Shandong province to Hunan province.

The Shandong provincial department of transport consequently suspended sleeper buses in the province.

The Ministry of Industry and Information Technology banned the production and sale of sleeper buses on March 1, and at the same time the Ministry of Public Security stopped the registration of businesses involved in sleeper buses.

There are more than 30,000 sleeper buses transporting passengers on more than 5,000 routes, according to a report by China National Radio.

In the other accident, a van carrying 12 people, including three children, hit the rear of a truck on a highway in Sichuan province on Sunday afternoon, leaving 11 people dead and one injured, according to Xinhua News Agency.

The truck had stopped on the emergency lane after it got a flat tire and the van smashed into it. The truck driver had gone to a garage when the accident occurred but his wife, who was in the truck, was not injured.

The police are still investigating the cause of the accident.