Three more people have been arrested over a shooting between two rival gangs in Sunderland - taking the total number of arrests to 15.
A shot fired at a window in Edgmond Court on Monday sparked a police response to the area.
No-one was in the property and no-one was injured.
However, officers believe it was the result of an on-going dispute between two groups in the city.
Yesterday, five men were arrested after two vehicles were stopped in Fulwell Road while more arrests were made as homes across the city were searched.
Since, then three further arrests have been made as officers continued to search properties taking the total number of those arrested to 15.
As police inquiries continue, detectives are warning their "robust response" to the illegal use of firearms will continue.
Earlier today Southern Area Command T/Superintndent Sarah Pitt said: “There has been an on-going dispute between two groups within the city which has culminated in an incident involving a firearm and associated criminal activity.
“Public safety is of the utmost priority to us and we will relentlessly pursue those responsible and carry out a robust response to stop this criminal activity immediately.
“I know incidents involving firearms can cause people to feel worried and unsafe and we cannot underestimate the impact this has on our communities.
“I would like to let people know we are doing everything we can to make sure everyone involved is arrested before this dispute escalates any further.
"Thankfully, the number of crimes involving firearms in the city is very low and do not happen very often. However, when they do, the small minority who do use firearms to commit crime can expect a robust response from police and we make no apology for this.
"Our efforts at stopping firearms being used will not stop at those who directly commit the offence, they will have a network of people assisting them - whether they're providing the firearm or helping the offenders cover their tracks - we will target them.
"We will be relentless in pursuing those involved and as we unravel the network of those involved there may be further police activity in the coming days and weeks and I would ask our communities are not alarmed by this. It is important that we take this action to prevent anyone coming to serious harm.
"Local communities will see an increased police presence as officers carry out high visibility patrols and again this is nothing for people to be alarmed by, they are there to provide reassurance and anyone who does have any concerns can speak to an officer on patrol."
Anyone with information about the incident on Monday or the on-going dispute is asked to contact Northumbria Police on 101 quoting reference 511 290216 or they can pass information to Crimestoppers anonymously on 0800 555 111.