A number of shots were fired at police in Londonderry in what has been described as a "blatant bid to murder police" while the federation representing officers described the violence as "an act of pure evil".
Chief Inspector Neil Beck said: “For a fourth consecutive night police officers dealt with violence and disorder. Around sixteen petrol bombs and five paint bombs were thrown from the Bogside area and, in what can only be described as a blatant bid to murder police officers, shots were fired at police close to our city’s walls.
"We believe that around six shots were fired striking the walls and nearby trees, however fortunately none of our officers were injured. Police officers should not be targeted under any circumstances and their lives should not be put in danger by simply doing their jobs, attempting to keep people safe.
"I am appealing to those with influence in the area to please assist us in trying to bring this unnecessary and unwanted violence to an end. This isn’t wanted by the community and those involved are urged to cease this activity immediately. "
Police Federation for Northern Ireland chair, Mark Lindsay, said: "Shots fired at our officers show the clear intent of those who have been orchestrating days of petrol bombing and assaults in Derry/Londonderry.
“The young people used to assault officers are being callously and coldly used by the dissident republican murder gangs who have murder as their main objective.
“Young people who throw petrol bombs or bricks or bottles need to know there will be consequences for them. As for the gangsters who use them as a shield, they will be pursued relentlessly and every effort will be made to bring them to justice.
“This attack last night was an act of pure evil, and attacks like this have got to stop. We have to see an all-out effort being made to rid communities of these ‘dinosaurs’ and to allow people to get on with their lives."
Sinn Fein MLA Karen Mullan said: “The people of this city have already made it clear that they are completely opposed to the violence that has been taking place in the Bogside and Fountain areas this week.
“So for an armed group to seek to exploit and escalate that is disgraceful. Earlier this week, we had dissidents denying involvement in orchestrating the trouble but now we see shots being fired and people are rightly asking who else would be responsible for that?”
“This was a reckless and highly concerning escalation that endangered lives. It should be condemned by all and those responsible should get off the backs of this community.”
UUP deputy Mayor of Derry City and Strabane District Council Derek Hussey said: “The attempted murder of police officers in the City of Londonderry overnight is absolutely abhorrent and is to be condemned.
"I am also disgusted that the Fountain Estate has had to endure yet another sectarian attack on what is a small Protestant community.
"There is clearly a very sinister element involved. Some have tried to play this down as kids acting up over the summer months. That is clearly not the case. These are well orchestrated, co-ordinated attacks on the PSNI and the Fountain Estate."
A number of males have been charged in connection with disorder over previous evenings and two of those are due to appear in court on Wednesday.
Police say they has a robust strategy in place to identify those involved in the trouble over recent days, saying they are confident of further arrests.
Anyone with information is asked to contact police on 101.