Labour leader Keir Starmer and London Mayor Sadiq Khan have condemned the 'unacceptable' actions of Manchester United fans during protests at Old Trafford.
The senior Labour politicians spoke out after about 100 United fans got onto the pitch, before the team were due to play Liverpool.
The club said the glass door to a disability lift was smashed to gain access.
Six police officers were injured, including one who suffered a 'significant' slash wound to his face after being attacked with a bottle.
Hundreds more protested outside the ground against the Glazer family's ownership of the club.
The game, which had been due to kick off at 4.30pm, was later abandoned due to safety concerns.
Sir Keir, an Arsenal fan, said he recognises the 'strength of feeling' but said people shouldn't 'resort to criminal behaviour'.
While Mr Khan claimed that 'unacceptable' acts by supporters 'let down the club they claim to love'.
Referencing the anger against the European Super League plans, which England's top clubs have now backed away from, Sir Keir said: "There's no doubt the strength of feeling of fans across the country at the plan to have a breakaway, which I think would rip football apart.
"I don't think anybody needs to resort to criminal behaviour in order to make their feelings known, but there is a very very strong sense of feeling that it's wrong, and it is wrong."
Mr Khan said: "I share the anger, the frustration and the heartbreak that many fans had of the behaviour of the six clubs who wanted to have a European breakaway super league.
"But I think it's really important for those that feel angry to filter and focus their anger in a lawful, peaceful way.
"Some of the scenes last night were unacceptable.
"I condemn the criminal behaviour, some of the actions are just not on.
"It lets down the club they claim to love, but also lets down those football fans who were waiting to watch the game on TV.
"My message to anyone who feels angry about this is organise, so you can make sure your views are heard in a lawful, sensible, peaceful way."
Andy Burnham, Mr Khan's counterpart in Greater Manchester, previously said he understands the concerns of United fans, but said there was 'no excuse' for the 'minority' who resorted to violence.
Speaking yesterday, Assistant Chief Constable Russ Jackson condemned the actions of some at protests at Old Trafford and the United team hotel as 'reckless and dangerous'.
He said an investigation has been launched and vowed to prosecute those responsible.
