Police say the clashes were isolated incidents

Two were given conditional discharges and one man was bound over to the court to ensure good behaviour.

The fourth supporter pleaded not guilty to possessing an offensive weapon and was bailed to return for trial later this year.

Police also charged 12 English fans. They will appear before magistrates on 18 April.

Isolated incidents

Hundreds of supporters were caught up in crowd trouble outside Old Trafford before Tuesday night's Champions League tie in which Manchester United beat Roma 7-1.

Before the match started there was a stand-off between rival fans who were separated by riot police and dog handlers.

Greater Manchester Police said incidents were "isolated" and were dealt with quickly.

A spokesman for Manchester United said they were "entirely happy" with the policing and security arrangements outside the ground.