SHANGHAI (REUTERS, AFP, NYTIMES) - Eighteen people were injured on Friday (Feb 2), three seriously, after a vehicle mounted the pavement in a busy part of central Shanghai and ploughed into pedestrians, the city government said.

Shanghai police statement said a preliminary investigation indicated that the crash was an accident. It added that the driver of the van, a 40-year-old man surnamed Chen, had been smoking while driving and that the vehicle had contained "dangerous substances" that apparently ignited.

In a short statement issued earlier, the Shanghai government said that the incident occurred at around 9am on a road running next to People's Square.

Zhang Sai, a security guard at an adjacent building, told AFP the van was on fire when it veered out of control and jumped the curb, striking some pedestrians and sending others scurrying to get out of the way. "It happened at around 8.50am. The van was on fire before it crashed on the sidewalk," he said.

The flames have since been extinguished and an investigation was underway, the government said, without elaborating.

Shanghai-based news portal The Paper said the vehicle was a minivan, and cited eyewitnesses as saying it was on fire as it drove onto the pavement, knocked people down and came to a stop in front of a Starbucks outlet.

Some bystanders tried to break the window of the vehicle and drag out the six people in the vehicle, including the driver, the report said.

Xu Xin, a 23-year-old restaurant employee, came upon the immediate aftermath during his morning jog to find injured people on the ground and bystanders calling emergency services.

Portable gas tanks that are often used to fuel stoves were inside the vehicle, he said.

"The fire department carried gas tanks from the van, like those used in restaurants," Xu said.

AFP journalists who arrived at the scene in the wake of the accident found the area had been quickly cleared by the authorities. A small police presence was standing watch and damage to the fencing could be seen.

Footage on Chinese social media, which could not be independently verified, showed smoke coming out from the vehicle and people lying flat on the ground injured in the street.

While the police statement did not suggest this was intentional, there have been cases in China of people seeking to settle personal scores who have carried out similar acts.

In 2013, five people died and dozens more were injured in downtown Beijing after a speeding vehicle bowled along a crowded sidewalk and burst into flames near the Forbidden City. In 2009, three people set themselves and their car on fire at Wangfujing, a shopping street just east of Tiananmen Square, in what was described as a protest over land seizures.

Starbucks has a major presence in China, where it has opened more than 500 outlets a year, creating some 10,000 jobs in the country annually.