An eyewitness has described the chaotic scenes as a large group of youths gathered to witness an apparent arranged fight in Derry on Monday evening.
Video footage of the fight has been shared by those who witnessed the incident on social media, and one eyewitness said that they and their neighbours were shocked by what they saw in the Glen area.
The local woman told the Journal: "It started out as a small group at the top of the green area at the Glen flield. I came out as I had forgotten something in the car and the group of ten people had turned into a group of around 50. That seemed to happen in the space of five-ten minutes. All the neighbours came out as well to see what was going on."
She said that there had been two fellows punching each other, while others had witnessed further skirmishes among a few of the youths gathered.
"They all just ran down and were spilling out onto the Glen Road and then ran down onto the Northland Road. They were actually just blocking the traffic and didn't care. They were stopping traffic, and cars were having to avoid them."
She said that the younths involved seemed to be aged 12/13 and upwards.
"It looks like something had been organised," she said, while urging parents to keep an eye on their children's whereabouts.
"I would also say to parents to warn their children about getting into fights and what they can result in," she said.
Police said they received a report of a large number of youths present at the Glen Road area.
Inspector Mullan said: “Shortly before 6:15pm, it was reported that around 100 youths had gathered in the area and were throwing stones at each other. The youths dispersed towards the Northland Road area upon arrival of police.
“It is critical that the young people who choose to engage in anti-social behaviour understand that it is unacceptable and it must stop. We do not want to criminalise young people, however if offences are identified we will deal with them robustly.
“Parents and guardians need to prevent young people from becoming involved or caught up in these activities. Know where your children are, who they are with, what they are doing and what they are arranging on their social media accounts.”
Sinn Fein Councillor Mickey Cooper ealier said that social media was used to promote the fight.
SDLP Councillor Shauna Cusack meanwhile described the incident as "disturbing".