British police were today questioning 21 football fans arrested during violent clashes before Manchester United's Champions League quarter-final against AS Roma.
Hundreds of supporters were caught up in ugly scenes outside Old Trafford before the last night's game — which finished 7-1 to United as they progressed 8-3 on aggregate.
The main stand-off took place at the front entrance to the stadium on Sir Matt Busby Way as riot police and dog handlers separated rival fans.
Italian fans were bombarded with bottles and cans of beer as they were subjected to weapon searches at the away end turnstiles.
Several Roma supporters criticised the delay in getting them into the ground before the vast majority of home fans arrived for the match.
The first signs of trouble were said to have been triggered by a group of about 30 Manchester United fans who attempted to charge through the police segregation line.
Eyewitnesses said a firework was fired by Italian fans at Manchester United supporters as bottles were then hurled between rival groups.
However, the vast majority of bottles were thrown from United fans as police attempted to capture the perpetrators on film by using hand-held video cameras.
Some of the United fans sang "Where are your famous ultras now?", a reference to the hardcore Roma supporters' group.
Greater Manchester Police said there were no reports of any injuries, but there were several walking wounded outside the stadium before the match.
Parents with young children in the Roma supporters' queue were led tearfully to safety as the wave of missiles continued up until kick-off when the crowds finally dispersed.
Fourteen of those arrested were English and seven were Italian, police said.
PA