A police officer and two other people were seriously injured after a car collided into a police dog vehicle in Sunderland's Mowbray Road, causing the street to be sealed off.
Northumbria Police said that it received a report of dangerous driving on Hylton Road at around 10.50am.
Police were deployed to the area after a silver Vauxhall Corsa was reported to be driving on the wrong side of the road and had collided with another vehicle before driving off.
The force said officers then received further calls from concerned members of the public at nearby locations.
A search for the vehicle was launched, involving the police helicopter, and whilst officers were responding to the incident, the car collided with a police dog vehicle on Mowbray Road.
Two suspects and a police officer were taken to Sunderland Royal with serious but non-life threatening injuries.
One of the suspects, a 30 year-old man, has now been arrested and is in police custody.
The police dogs involved were checked over by a vet and are not seriously injured.
A spokesman for North East ambulance Service said: "We were called today at 11.30am with a report of a road traffic collision.
"We dispatched two double crews and one hazardous area response team.
"Three patients were taken to Sunderland Royal."
A police cordon was put in place in the street.
Police are appealing for any witnesses who may have seen an incident involving this vehicle today.
Any witnesses, or those who may have dashcam footage, are asked to contact police on 101 and use the reference number 301 30/12/18.