Police in Portadown have used water cannon to tackle rioters who were attacking them.

Officers were targeted with petrol bombs, fireworks, masonry, bricks and bottles.

The disturbance in the West Street area marked the Country Armagh town’s second night of unrest, but was at a lower level than seen earlier in the week.

Unrest started on Monday after a peaceful protest over an alleged sexual assault in Ballymena in County Antrim and later spread to other areas.

Earlier on Friday, police released photos of four suspects they wanted the public to help identify in connection with the disorder.

Dozens of officers in riot gear were involved in the operation in Portadown, forming lines in the town on Friday night.

Police said 63 of their officers had been injured over the previous four nights of violence after coming under “sustained attack”

Speaking at a press conference, Assistant Chief Constable Ryan Henderson said: “It is in all of our interests and in the interests of justice that those responsible are dealt with.”

“In releasing these images, I am asking the wider community to step forward and help us to identify these people,” ACC Henderson told a press conference on Friday.

Police have made 17 arrests following disorder in various parts of Northern Ireland.

“We’re actively taking steps to find you and we will bring you to justice,” ACC Henderson said.

“Our public order inquiry team has been working night and day to identify those involved.”

He also said police were investigating “those posting hate on social media”.

ACC Henderson said earlier in the week police had “no intelligence” about co-ordination from loyalist paramilitary groups in the disorder, but now he was “absolutely sure” that “we have seen people associated with those groupings at protests and particularly at disorder and in the vicinity of it”.

“I want to say that we will prosecute anyone without fear or favour who has committed crime and committed disorder regardless what their involvement or what group they might be involved with,” he added.

The assistant chief constable said police had seen some co-ordination in Thursday’s disorder.

“We did absolutely see in Portadown last night people who were directing young people and directing others back and forwards to try and get around police lines, find weak points, throw weaponry,” he said.

“So we certainly saw more co-ordination in the activity last night than we had seen in previous days. As to who was dong that co-ordinating, I’m not in a position to say yet.”

The first protest was organised hours after two teenage boys appeared before Coleraine Magistrates’ Court.

They spoke through an interpreter in Romanian to confirm their names and ages. Their solicitor said they would be denying the charges.

The worst of the disorder was in Ballymena, but unrest also spread to other towns.

In Portadown on Thursday a crowd pulled bricks and masonry from a derelict building, which they then threw at police.

ACC Henderson said his officers came under “significant and sustained attack”.

“It was clear that those involved were intent on destroying homes and businesses within the town and on attacking police,” he said.

“The police lines came under attack from heavy masonry, fireworks, petrol bombs and beer kegs.”

In Larne in County Antrim, masked youths attacked a leisure centre and set it on fire on Wednesday.

The centre had been providing emergency shelter for families following the clashes earlier this week.

The home of a family with three children was set on fire in Coleraine on Thursday night, in what ACC Henderson called an “awful, hate-motivated attack”.

Meanwhile in Bangor in County Down, graffiti stating “24 hrs” and depicting a crosshair were daubed on a home.

Alliance Party assembly member Connie Egan described it as “racist and intimidating”.

“Those who go out to deliberately stoke tension and inflame division in our area with this kind of harmful rhetoric do not represent the vast majority of residents here, and we simply cannot tolerate it,” she said.

Appealing for “calm” over the weekend, ACC Henderson said there would be a large police presence across Northern Ireland.

“For those thinking about causing disorder or coming to watch it, stay away, there will be consequences,” he added.