Chinese authorities took almost 24 hours to officially disclose the incident, which took place on Monday night in Zhuhai, a city of about 2.5 million people in southern China near Macau.
Images and videos showing dozens of people knocked to the ground and a car fleeing from the scene, which circulated on China's major social media platforms on Monday night, were swiftly censored.
Angry comments about the official delay in reporting the incident were also removed, and the Weibo messaging site censored a hashtag that mentioned the death toll.
Police say a man who was upset over his divorce settlement rammed his car into a crowd, killing 35. (AP PHOTO)
Police said the 62-year-old driver, with the surname Fan, had been captured and was hospitalised for wounds believed to have been self-inflicted with a knife to the neck and other parts of his body.
Fan had been upset about the split of assets in his divorce settlement, police added.
Candles and flowers had been laid at the scene on Tuesday evening.
About 30 people gathered around one of the gates of the sports centre, with delivery drivers on bikes stopping to add to about 20 bouquets laid in a row.
Hundreds of rescue personnel from Zhuhai city and Guangdong province were deployed to provide emergency treatment and more than 300 healthcare workers from five hospitals worked around the clock to save lives, state media Beijing Daily reported.
The attack happened as Zhuhai captured China's attention with the People's Liberation Army's largest annual airshow, where a new stealth jet fighter is on display for the first time.
"I was driving nearby last night and heard sirens everywhere, I thought it was for the airshow but then I've never heard sirens so loud before," a taxi driver surnamed Guo said.
"Then the passenger said there'd been a hit-and-run, I didn't realise it was so bad."
Others expressed shock.
"I don't know what to say but I hope this kind of sickness does not spread," a Weibo user wrote.
The death toll "makes every pore on my body stand on end," said another.
There was no indication that the attack was related to the airshow.
But it was the second such incident to occur during the Zhuhai airshow: in 2008, at least four people were killed and 20 injured when a man drove a truck into a crowded schoolyard during the airshow.
Police said that attacker had been seeking revenge over a traffic dispute.
President Xi Jinping, cited by Chinese state television CCTV, ordered all-out efforts to treat the injured and demanded severe punishment for the perpetrator.
The central government has dispatched a team to provide guidance on handling of the case, CCTV said.
Violent crime is rare in China due to tight security and strict gun laws.
However, a rise in reports of knife attacks in large cities has drawn public attention to safety in public spaces.
The deadliest attack Reuters was able to identify in recent years in China took place in Urumqi, in China's western Xinjiang region, in 2014 in which suicide bombers killed 39 people and four of the five attackers also died.
