The admission contradicted earlier statements by Durham Police that no shots had been fired during the arrest of three men suspected of firearms offences.
Onlookers who witnessed armed police stop the suspects' van in Yarm Road on Sunday said they heard shots seconds before the vehicle came to a halt.
The force said last night that plain-clothes armed police travelling in unmarked cars shot the van’s tyres, using an "approved" enforced stop tactic to box the van in which is designed to intercept armed suspects.
The same technique was used in Tottenham, north London, when 29-year-old Mark Duggan was killed after police stopped a taxi in which he was travelling.
Durham Police insisted the public were not at risk during the Sunday teatime drama and said the incident would not be referred to the Independent Police Complaints Commission because no one had been injured.
The van mounted the pavement and came to a stop against a garden wall, where it was surrounded by several police armed with machine-guns.
Three men, who were travelling in the van, were forced to the ground and held at gunpoint before being led away by officers and arrested on suspicion of firearms offences.
The men, aged 30, 22, and 19 from across the North-East, were tonight (Monday, February 17) being held at police stations across the region.
No one was injured in the incident, which unfolded on one of the main routes in and out of Darlington at about 5.30pm last night (Sunday, February 16).
One witness told The Northern Echo: “We heard a big bang and wondered what it was. It was really scary. It was right near my house.
“It looked like there was a fight and I thought, oh my god, phone the police - and then I saw it was the police.”
The enforced stop technique – also known as a hard stop - is a pre-planned tactic used by armed, plain-clothes officers in unmarked vehicles to deliberately intercept a vehicle to confront and detain armed suspects.
Former North Yorkshire police officer Mike Pannett said: “Every day police officers deal with dangerous and often armed criminals and these hard stop techniques are used all the time in places like Manchester and London.
“Sometimes it is too dangerous for officers to stop a vehicle like they normally would and these officers are ready for any threat whatsoever.
“We have got some of the most experienced firearms officers in the world."
Chief Superintendent Graham Hall of Darlington police said the incident was dealt with swiftly and safely.
He said: “The men were quickly arrested and are now in custody helping us with our enquiries. It is normal procedure for armed officers to be deployed to incidents of this nature and there is no need for alarm.
“Fortunately incidents like this are rare and I would like to reassure the community of Darlington and in particular the residents of Yarm Road that this is an isolated incident.”
Dozens of uniformed officers also attended the incident and closed Yarm Road, between Bright Street and Cobden Street, during the operation.