Revellers started a large street fire and battled police and fire crews who tried to intervene after St Patrick's Day celebrations got out of hand in a town in Canada.
Police in London, Ontario, said at least 11 people had been arrested so far, and more arrests were expected as authorities reviewed video of the disturbance and witness statements. At least 17 police vehicles were damaged. No serious injuries were reported.
The trouble began on Saturday night when a crowd of about 1,000 people, many of whom had been drinking, celebrated in the streets in a district near Fanshawe College heavily populated by students which has been the site of previous smaller disturbances.
District Fire Chief Jim Holmes said fire crews were called to the scene after revellers flipped over a TV news van and set it on fire, but were driven back when some people in the crowd pelted them with rocks and bottles.
The vehicle exploded and partygoers fed the street fire with furniture, mattresses, fences, uprooted trees, a large TV set, and even a 20lb propane tank. Authorities said the crowd continuously threw bricks and beer bottles at police officers and refused to allow fire crews to douse the blaze in a scene police likened to a war zone.
Police and fire crews made the decision to stand back to avoid escalating the situation further, but eventually moved in around 4am when the crowd had thinned out. Authorities estimated the damage at £63,000.
"Going in there with that number of people might not have been good for anybody. So we just kind of stayed back and were patient until we decided it was time to move in," Mr Holmes said.
Police said they would work with residents and college authorities to ensure that similar disturbances would not occur in the future. "Never in my 32 years as a police officer have I observed behaviours that escalated to the point where there was risk that individuals could seriously be hurt or quite frankly killed," London's chief of police Brad Duncan said.
"We will not tolerate this lack of respect for our community, our laws and specifically this neighbourhood."