It is the latest public outcry involving "chengguan", or urban management officers, who have gained particular notoriety among the Chinese public for abusing their power while enforcing city laws.

Street vendors in China often operate without licences, and can be fined for doing so.

When the fruit sellers in Zhejiang province's Hangzhou city spotted four chengguan patrolling the neighbourhood on Thursday, they got in their truck to flee, accidentally running over their son, Channel 6 TV quoted eyewitnesses as saying.

A surveillance video aired by the Zhejiang provincial station showed the father, surnamed Liu, getting into the vehicle on the driver's side while his son played on the ground, ahead of the front wheel on the passenger side.

As the chengguan chased other vendors around the street corner, the father began driving away, crushing his son under the wheel, the video showed.

"By the time I had passed by after work, the child had already passed away, and they were standing around crying," one local man told the station.

A police statement cited by the Beijing News confirmed the incident on Thursday and said that an investigation was ongoing.

Some users of China's popular online social networks responded to the report with rage, questioning why vendors should be so fearful of chengguan.

"This is devastating. Why does China need chengguan in the first place?" one poster wrote on Sina Weibo, a Chinese version of Twitter.

Others pointed the finger at the couple for not taking better care of their child.

"You really can't blame the chengguan. The father cared only about himself and not his son," wrote one.

Another added: "If you let your child run around all over the street every day, then tomorrow won't he get run over by a car? This is entirely due to the negligence of the parents."

In one of the highest-profile incidents involving chengguan in recent years, four officers in the central province of Hunan were sentenced in 2013 to between three and a half and 11 years' jail over a dispute that left a roadside watermelon vendor dead.

Local media reported that the officers beat the vendor to death for operating without a licence, with one smashing his head with a metal measuring weight.