Four people are being questioned after riot police were called to control a protest which led to demonstrators storming a south London town hall.
Three men and a woman were arrested at Lewisham Town Hall on Monday evening after a crowd gathered to protest over council cuts and tuition fees.
Some forced their way into a council meeting and had to be removed.
The Metropolitan Police (Met) said 15 officers suffered minor injuries, with two needing hospital treatment.
Police said that one suffered a broken finger while the other was treated for the effects of inhaling smoke from flares carried by some of the protesters.
A Met spokesman said a 21-year-old man was arrested for violent disorder, a 31-year-old woman for aggravated trespass, a 36-year-old man for violent disorder and trespass and a 28-year-old man for possession of an offensive weapon.
The spokesman said there had been a small protest outside the building from about 1730 GMT but the trouble flared after about 100 others arrived at 1830 GMT.
Kate Belgrave, a journalist who was at the town hall, said: "It was pretty full-on outside the town hall.
"People were told the public gallery was restricted to 28, and then they rushed at the entrance shouting 'let us in'."
Sue Luxton, who was also at the protest, said: "I was a councillor until May for the Green Party, but I'm now a teacher. I wanted to peacefully express my anger at the cuts.
'Overwhelming the police'
"Many (of the protesters) wanted to get in to hear the meeting, but they were only allowing 40 people in and there was to be no videolink room, which there often is.
"People were angry that they couldn't get in, especially as it was so cold.
"More people managed to get in by overwhelming the police after the initial 40 had gone in.
"The police sent horses, police cars, stopped the buses and cordoned off the road."
Nearby streets, including the A205 South Circular Road, were cordoned off for about an hour on Monday evening, but have now reopened.