Thursday 19 February 2015 21:18, UK
Police arrested 23 Feyenoord fans in Rome after trouble flared before the Dutch side's Europa League clash with Roma on Thursday, Italian authorities said.
Buildings were damaged and bottles were thrown at riot police on Wednesday night, with trouble continuing on Thursday.
Hundreds of Feyenoord fans clashed with riot police at the Spanish Steps, while tear gas was fired at fans as they left the square's Baroque fountain full of empty beer bottles.
"This violence is unacceptable," said Rome mayor Ignazio Marino on his Twitter account.
"I have filed a complaint and asked for an explanation to the people who should be taking care of public order in this city."
Feyenoord "should make a public apology", added Livio Ricciardelli, a member of the city government, saying that repairs to the fountain at the bottom of the Spanish Steps would be costly.
"Feyenoord should pay for the damage caused to the city by its fans," he said.
Around 6,500 Feyenoord supporters are expected to attend the last 32 first leg match at the Stadio Olimpico.
