A minivan crashed onto a pavement in a busy district of downtown Shanghai early on Friday morning, leaving 18 injured.
Three of the injured were reported to be seriously hurt.
Authorities said they believe the crash was an accident and not an attack, and claimed the driver was smoking while transporting gas tanks.
The van veered onto a pavement and burst into flames at about 9am near People's Park in the heart of the Chinese financial hub, the city government said on its social media account.
The cause of the crash is under investigation.
Local media reported the vehicle was carrying six people and several tanks of gas when it swerved off the road.
Videos on social media showed people lying unconscious on the pavement next to a Starbucks cafe and firefighters trying to extinguish a blaze inside the van.
The crash comes as British Prime Minister Theresa May is scheduled to speak in Shanghai.