A dedicated garda unit is trawling through various social media platforms in an effort to prevent the online organisation of mass street brawls.

One of the country's most senior garda officers has said fights organised on websites such as Facebook "are a recurring problem" for gardai in the capital.

Assistant Garda Commissioner Jack Nolan, who is responsible for policing in the Dublin Metropolitan Region (DMR), added that investigations would continue into the organisation of mass brawls through social media.

It comes after four youths were arrested following a mass public order incident involving more than 200 teenagers in the north inner city on St Stephen's Day.

Youths gathered on Mary Street and surrounding streets throughout the day, with viol- ence erupting shortly after 5pm.

A number of people were assaulted, while some shopkeepers on the street were forced to pull down their shutters.

"With regards to social media fights, certainly I am aware of the incident happening on Henry Street and Mary Street on St Stephen's Day," Mr Nolan told the Dublin City Joint Policing Committee (JPC).

"I have people actually continuing to trawl through social media for any indication of anything like that.

"A number of people have been arrested in relation to what happened on St Stephen's Day and other investigations are continuing.

"It is not a new problem, it's a recurring problem periodically, but we will keep on top of that."

The specialist garda unit is also used to monitor the social media accounts of known criminals to detect any unusual or suspicious behaviour.

Riot

Rival gangs of teenagers, totalling more than 200 youths, were involved in the "mini riot" on St Stephen's Day, which was arranged through Facebook.

Two groups of teens, mainly from Blanchardstown and Tallaght, arranged the bust-up, and a number of fights were filmed and shown on Snapchat.

City councillor Nial Ring, a member of the Dublin Central JPC, previously told the Herald: "More gardai are needed on the streets now. Businesspeople are trying to make a living and young people can't be allowed to be running around out of control.

"There are 130 fewer gardai on the beat in the city centre because of cutbacks.

"Gardai can't effectively police these mass activities without proper manpower."

Mr Ring also said gardai in the north inner city would need to liaise with colleagues from the areas where the teenagers originate, while continuing to trawl social media.

"Gardai will need to monitor Facebook and Snapchat to identify the perpetrators and liaise with their colleagues in Tallaght and Blanchardstown," he said.

City councillor and former Lord Mayor Christy Burke, who is also on the policing committee, said: "Gardai in the inner city are already very busy policing the gangland feuds without having to deal with something like this as well.

"This behaviour could get more out of hand if other young people start to follow suit. Gardai have to deal with this problem rapidly."