The toll from the Monday incident was a dramatic increase from the initial report, when police only said that people had been injured, with videos apparently scrubbed from social media.

A 62-year-old man surnamed Fan drove a small SUV through a gate and "forced his way into the city's sports centre, ramming people who were exercising on the internal roads", police said Tuesday.

Preliminary investigations suggested Fan's attack had been "triggered by (his) dissatisfaction with the division of property following his divorce", their statement said.

Footage from Monday night geolocated by AFP showed people lying motionless on the ground, while others were seen frantically attempting to resuscitate the unconscious.

An eyewitness surnamed Chen told Chinese news magazine Caixin it was common for groups to take daily walks on the dedicated track around the stadium.

He had just completed his third lap on Monday when a car suddenly sped at them and knocked down "many people", but he was able to jump aside.

Another eyewitness surnamed Liu told Caixin that the car "drove in a loop".

"People were hurt in all areas of the running track -- east, south, west, and north," he said.

Fan was "controlled on the spot" as he attempted to drive away, police said Tuesday.

He was found in his car cutting himself with a knife, and is currently in a coma after self-inflicted injuries to his neck and other parts of his body, unable to undergo interrogation, they added.

The 43 people wounded are not currently in life-threatening condition, police said.

Chinese President Xi Jinping has urged "all-out efforts" to treat the injured and has "demanded punishing the perpetrator in accordance with the law", according to state news agency Xinhua.

China's largest airshow showcasing Beijing's civil and military aerospace sector is being held in Zhuhai at the moment.

- 'No filming' -

There were fewer than 20 people at the sports stadium on Tuesday night when AFP visited the scene.

Some were attempting to take videos but were blocked by a police car and security guards shouting "No filming!"

At another entrance, candles flickered at a makeshift memorial where people were sending online flower deliveries. One delivery driver said he had already brought 10 orders there that night.

"Zhuhai is supposed to be the safest city, nothing like this has ever happened here in the last decades," one resident told AFP.

A shocked young man told AFP he normally went running around the sports centre every night -- but hadn't on Monday as he was tired.

He lamented the media coverage of the incident, saying that in the past, local outlets would have pressed authorities for answers.

At around midnight, cleaners doused out the candles, and workers took away flowers, saying they had been ordered to move them to a different location and that the public could view them tomorrow.

Some of the workers told AFP the decision to move the flowers was an "order from the top."

Videos on social media earlier showed Zhuhai residents queuing up at blood donation centres and hospitals.

Security was high in front of the emergency room of a hospital near the crime scene, and a huge group of doctors and nurses was milling about.

- Safety alert -

In a safety alert, Japan's embassy in China warned its citizens on Tuesday to be on high alert and "refrain from speaking loudly in Japanese and avoid provocative, attention-drawing behaviour such as being loud in groups".

The embassy said it had no information that any Japanese citizens had been wounded in the attack, but noted China has seen a spate of violent public attacks in recent months.

In September, a Japanese schoolboy was fatally stabbed in the neighbouring city of Shenzhen, prompting outrage from Tokyo.

A man killed three people and wounded 15 in a knife attack at a supermarket in Shanghai in October.

And in July, police said a vehicle crashed into pedestrians in the central city of Changsha, killing eight.