A burning van that careened onto the sidewalk injuring 18 people in downtown Shanghai on Friday morning was driven by a suspect who was allegedly smoking while illegally transporting hazardous substances, police said.

The van with a Jiangxi license plate caught fire and diverted into the sidewalk on Nanjing West Road at 8:57 am injuring the driver and 17 pedestrians, police said.

The 40-year-old driver from East China's Jiangxi Province was working for a Shanghai metal company, according to a Shanghai Huangpu police notice released Friday noon on its official Sina Weibo social media account.

All victims are being treated at hospital.

"Knowing that the van might explode, many people still stood out as they helped with the rescue," a man, who witnessed the incident while on the way to work, told the Global Times. He asked to be anonymous.

The incident happened at the west corner of Renmin Square in central Shanghai, outside a Starbucks. The witness was around 100 meters away before he heard people screaming. When he arrived at the spot a minute later, he saw the van was on fire, and four or five people were under the van.

He and several witnesses soon rushed into a nearby Starbucks and borrowed fire extinguishers to put out the fire and to rescue the victims. He said that he did not see a driver in the van, but saw some liquefied gas bottles.

In five to 10 minutes, the police, firefighters and ambulances all arrived on the scene. The police sealed off the area, the witness said.