Four people have been arrested - including a woman on suspicion of causing grievous bodily harm and possessing a firearm - after a police officer was shot in Nottingham city centre.
Nottinghamshire Police said the officer had approached two suspects in Angel Row shortly before 04:50 BST on Sunday.
The male officer remains in hospital and is in a stable condition, the force added.
Two women, 27 and 25, and a 24-year-old man were arrested after police stopped a vehicle in the Radford area of Nottingham on Sunday evening, while a 30-year-old man was arrested in Bedfordshire in the early hours of Monday.
The 27-year-old woman was arrested on suspicion of causing grievous bodily harm with intent, and possession of a firearm with intent to endanger life.
The 24-year-old man and 25-year-old woman were also arrested on suspicion of assisting an offender.
Separately, after stopping a vehicle in Bedfordshire, the 30-year-old man was arrested on suspicion of assisting an offender.
Assistant Chief Constable Claire Rukas said: "A team of experienced detectives continues to work tirelessly to establish exactly what happened before, during and after this appalling incident.
"I am pleased that four arrests have now been made and hope this provides some reassurance to the public as those detained are questioned in connection with the discharge of the firearm."
A large police cordon - which was put in place in Angel Row following the shooting - has now been lifted.