Manchester United manager Ole Gunnar Solskjaer has backed the right of fans to protest, but said they needed to be “civilised” after Sunday’s breach of security at Old Trafford led to their Premier League game against Liverpool being postponed.

United fans stormed Old Trafford on Sunday and invaded the pitch, while protesters also clashed with police outside the ground, with six officers injured during the demonstrations.

Solskjaer said the Glazers were working to improve their communication with supporters and that he had received a personal apology from the American owners.

“We have to listen, to hear the fans’ voice,” Solskjaer told on Wednesday. “It’s everyone’s right to protest but it has to be in a civilised manner.

“Unfortunately when you break in, when police officers are scarred for life, that’s a step too far. I’ve been communicating with the owners and I’ve had a personal apology. ”

The postponed match has been rescheduled for May 13, the league said on Wednesday.

United thrashed AS Roma 6-2 in the first leg of their Europa League semi-final tie at Old Trafford and Solskjaer hopes his players can put the events out of their minds and focus on reaching the final.