The youngsters were among six injured in a crash between two cars after five traffic lights and Ulez cameras were destroyed in Orpington, south London at 8.30am onThursday morning.
Police had been managing the traffic at the time of the collision hours after the cameras were cut to the floor at a busy junction on Court Road and Old Priory Avenue.
Locals said they saw one young girl aged around 7-years-old bleeding from the face.
One witness Phil told The Independent: “The accident had already happened before I arrived but I could see a few children in one of the cars.
“I don’t agree with extending Ulez into the suburbs but putting our kids at risk is taking it too far.”
A Met spokesman said two were assessed and their condition was confirmed to be non-life threatening.
He added: “We are aware of criminal damage to five sets of traffic lights in the Orpington area this morning Chief Inspector Priya Shome, based in Bromley, said the crimes had taken up valuable policing resources in the borough.”
CI Shome added: “Two police units, who should have been available to answer 999 calls, were instead required to spend the morning managing traffic.
“The people who are carrying out this criminal damage are putting the public at risk.
“This morning, there has been a collision between two cars on Court Road, at the location of one of the damaged traffic lights, in which a child was injured.
“I would urge the people carrying out these crimes to stop immediately.”
A London Ambulance Service spokesperson said: “We sent resources to the scene, including ambulance crews, a medic in a fast response car and an incident response officer.
“Our first medic arrived on scene in approximately four minutes.
“We treated six patients at the scene before taking them all to hospital.”
The crash came as two men were arrested after a Ulez camera was blown up the same day it was installed.
Counter-terrorism officers from the Metropolitan Police investigating the incident said the camera was blown up using a “low-sophistication improvised explosive device” (IED) at about 6.45pm on December 6 in Sidcup, south-east London.
At the time, a spokesperson for the Mayor of London called the incident “grotesquely irresponsible” and the incident was believed to have been a “deliberate act”, according to the London police force.
No one was injured during the explosion but vehicles and a residential property suffered damage.
Fgures released by the Met in November showed nearly 1,000 crimes linked to Ulez cameras being stolen or vandalised have been recorded in the past seven months.
The Ulez zone was expanded in August to cover all of London’s 32 boroughs. Those who drive in the area with a vehicle that does not meet emission standards are then charged a £12.50 fee.
After the incident a spokesman for mayor of London Sadiq Khan said: “This grotesquely irresponsible behaviour puts both lives and property at risk. Police are rightly investigating this dangerous and reckless act.”