Police say they have now arrested 21 people after a gunshot was fire at a house in Sunderland.
Last Monday, February 29, a window was shot at in Edgmond Court in Hollycarrside.
Police believe the incident was as a result of an ongoing feud between two rival groups in the city and for the past week police activity has been on-going throughout Sunderland and Newcastle.
A man was arrested earlier today taking the total arrests so far to 21 - three of those have been charged.
A house in Sunderland has also been searched and items seized.
Yesterday, search warrants were carried out at houses in Sunderland and Newcastle, with mobile phones seized by officers. And, police have uplifted a vehicle as part of enquiries.
Detectives working on the investigation say they will not stop pursuing those involved as high visibility patrols continue to offer reassurance to the public.
Southern Area Command Chief Inspector Paul Milner said: "Over the past week police have carried out daily activity to disrupt the lives of those involved in this feud.
"It has escalated too far and we are doing everything we can do put a stop to it.
"And, as our enquiries continue and we uncover wider criminal activity we will make sure all of those involved are apprehended.
"More than 20 people have been arrested so far and we expect this to continue, more warrants will be carried out and more houses searched.
"Items will be seized by police and vehicles stopped and checked.
"We will work with our partner agencies such as HMRC and Trading Standards to work together to disrupt these organised groups.
"Our disruption activity will continue for as long as it needs to - we will not stop until those involved stop and we make no apology for this.
"We know increased police activity can cause concern to our local communities but I hope they can see why it is necessary and ask they are not alarmed by this.
"High visibility patrols will continue throughout the city who are there to offer reassurance and anyone who is concerned can speak to an officer on patrol."
Anyone with information about the incident last Monday or the on-going dispute should contact Northumbria Police on 101 quoting reference 511 290216.