Multiple arrests were made on Saturday night as hundreds of teenagers gathered in Cork city centre.
The crowds were described as “menacing” by one witness and they prompted numerous local businesses to close early.
Videos taken over the weekend showed large crowds of youths gathering in the city centre, some videos showed people apparently injured on the ground being tended to by gardaí.
Active patrols were carried out by gardaí throughout the evening and arrests were made for Public Order Incidents.
“The policing of anti social behaviour is an ongoing priority for An Garda Síochána,” a garda spokesperson said.
Seamus Kearney, a UCC student who lives in the city centre, said that the mood in the city darkened and became very volatile at about 10pm around Grand Parade, Daunt Square and Cornmarket streets.
“There was a menacing atmosphere in certain parts,” he said.
“The fighting kicked off at about 10pm before parents arrived to collect people and take them back to the suburbs.
“One person I saw was injured and taken to hospital.
“Some people, particularly young boys, 15-17, were fighting.
“The guards were great but they can’t be everywhere at the same time.
“Two ambulances were called for one fight outside Hillbillies.”
Mr Kearney said that he was verbally abused by one group of young teenagers as he cycled down Oliver Plunkett Sstreet.
“I didn’t see myself in personal danger but it might have been dangerous for some people,” he said.
"The council was very good though, they were around today and cleared up all the broken glass.”
Earlier that evening, local business owner Ernest Cantillon, proprietor of Electric bar and restaurant in the city, said that approximately 300 young people, aged between about 16 and 20, gathered on the boardwalk outside his business at about 7pm on Saturday night.
He stopped serving drinks one hour early because of the large crowds.
But although the groups were somewhat boisterous, he didn’t see any trouble and when gardaí arrived at 7.40pm, the crowds dispersed peacefully.
A crew from Cork County Council arrived shortly afterwards and the park and boardwalk were “spotless” by 8pm, he said.
“It was very busy but I didn’t see any public order incidents," he said.
“It was our third-weekend serving takeaway drinks but we closed that because it was too busy.
“I can see how someone could be intimidated by a crowd of 300 people because of the noise, but I couldn’t see any harm in it.”
Independent Councillor Ken Flynn said that large gatherings of youths are not limited to the city centre.
Approximately 40 youths gathered in an estate on Dublin Hill in the Northside of the city and up to eight wheelie bins were stolen and burned out.
“I’m hearing reports of people meeting up in groups in various neighbourhoods," he said.
“It’s a time for us all to be vigilant. We don’t want to be back in another lockdown.
“I appreciate how everybody is frustrated and as the restrictions ease I think it will get easier on people.
“But people must still be vigilant. People must know and should know where their teenagers are. Where their under-18s are. And people who are over 18 need to take responsibility for their actions as well.
“Most people are behaving themselves, most people are annoyed and frustrated but they’re getting through it. It’s sad to see that others are not taking it as seriously as they should,” he said.