SHANGHAI (AP) — A minivan hauling gas canisters whose driver ignited his vehicle while smoking plowed into pedestrians near a prominent park and burst into flames in downtown Shanghai on Friday, injuring 18 people in the heart of the Chinese financial hub, local authorities reported.

Police appeared to dismiss fears that the crash was a deliberate attack, describing it as an accident caused when the driver lost control and veered onto the sidewalk.

The 40-year-old driver, whom police identified only by his surname Chen, and two other people suffered serious injuries. Chen works for a Shanghai metals company and had no criminal record but is now under suspicion for transporting dangerous materials, police said.

"It couldn’t stop, crashed into the corner and caught fire," said a cleaner who works in a building across the street from the crash site. Like many Chinese, she asked only to be identified by her surname, Xu.

She told The Associated Press she saw smoke coming out of the van as it drove down the street before careening out of control.

The minivan, registered in the southern province of Jiangxi, veered onto a sidewalk and burst into flames around 9 a.m. near People’s Park, authorities said.

The vast city center plaza is also home to the headquarters of the Shanghai municipal government, which oversees a metropolis of almost 25 million people that is widely regarded as China’s most cosmopolitan city.

The website of the local Xinmin Wanbao newspaper and other local news outlets said the van struck five to six people waiting for a light change at a busy pedestrian crossing.

Videos on social media showed injured people lying on the pavement next to a Starbucks cafe and others pinned under the tires of the van. Firefighters were seen trying to put out a blaze inside the vehicle.

Xu, the cleaner, told AP she saw two men struggling to pull a passenger out of the van. "Other people told them to stop. Then the police and ambulance arrived," she said.

The Shanghai-based news outlet Pengpai, citing a witness, reported that the vehicle was carrying six people and several canisters of gas typically used for cooking and heating.

A man who witnessed the crash on his way to People’s Park said in a video interview carried by Chinese media outlets that the minivan seemed to be moving fast as it veered across the road.

"The minivan did not slow down. The driver must have been in a panic at the time. He didn’t slow down and just directly crashed," said the witness, who wasn’t identified. "It was on the other side of the road and made a turn over to this side. People saw it and quickly tried to get away but a lot of people were still hit."

The man said people cracked open the windows of the vehicle trying to rescue passengers who appeared to be unconscious. Firefighters removed liquefied gas canisters from the vehicle, he said.

At the nearby Changzheng Hospital, Shanghai resident Liu Axing told AP that his daughter, Liu Jianying, was crossing the street on her way to work when she was struck by the van.

She was undergoing surgery for a broken shoulder and pelvis, Liu said as he pulled up a picture on his phone of his daughter pinned under the vehicle’s front wheel, seemingly unconscious.

Three people were more seriously injured than her, Liu added.

A relative of one patient in the emergency room, who declined to be identified, said at least five or six crash patients were being treated there.

While indications showed the crash was an accident, vehicle attacks have killed scores globally in recent years, most recently in New York City in October when eight people were killed by an attacker claiming allegiance to the Islamic State group.

In China, five people, including three attackers, were killed in 2013 when a four-wheel drive vehicle plowed into a crowd in front of Tiananmen Gate in the center of Beijing. The attack was blamed on separatist extremists from the Turkic Muslim Uighur ethnic group native to northwestern China.

Friday’s crash occurred just as British Prime Minister Theresa May was speaking at a business event in Shanghai. May’s speech was at a forum in the Lujiazui district on the opposite side of the Huangpu River from People’s Park.

Other speakers at the event included Li Shufu, the chairman of Chinese carmaker Geely, and Nobel Prize-winning physicist Kostya Novoselov.

May on Thursday met with Chinese President Xi Jinping in Beijing as part of her three-day visit aimed at establishing a new trading relationship after Britain leaves the European Union.

The crash also comes at the start of the Lunar New Year travel period, when hundreds of millions of people return to their hometowns for the most important family holiday of the year. During the weeks-long period, authorities emphasize safety on the road and aboard planes, trains and ferries.

Friday’s incident bore the characteristics of an accident rather than a terrorist attack because of the lack of any apparent effort to deliberately ignite the gas canisters, said Li Jing, a professor of disaster management at Beijing Normal University’s School of Social Development and Public Policy.

"Because of his complete ignorance of safety rules, his action has amplified harm and risk to the public resulting in such casualties," Li said of the driver.

Li said the incident also points to the need for increased safety awareness in China, where gas canisters and other highly dangerous objects are sometimes transported on flatbed tricycles even in major cities such as Beijing.

"It indicates how urgent it is for the government to step up promotion of public safety knowledge and awareness," Li said.

Hours after the crash, Shanghai police posted a social media message warning drivers to "never, ever smoke" — or toss cigarette butts in proximity of flammable objects.

Shih reported from Beijing. Associated Press researchers Fu Ting and Si Chen contributed to this report.