Manchester United's Premier League game against Liverpool was postponed on Sunday after supporters stormed into the stadium and onto the pitch as thousands of fans gathered outside Old Trafford to demand the Glazer family ownership sells the club.
Long-running anger against the American owners has boiled over after they were part of the failed attempt to take United into a European Super League.
United and Liverpool players were unable to travel to the stadium.
"Following discussion between the police, the Premier League, Trafford Council and the clubs, our match against Liverpool has been postponed due to safety and security considerations around the protest today," United said in a statement. "Discussions will now take place with the Premier League on a revised date for the fixture.
"Our fans are passionate about Manchester United, and we completely acknowledge the right to free expression and peaceful protest. However, we regret the disruption to the team and actions which put other fans, staff, and the police in danger. We thank the police for their support and will assist them in any subsequent investigations."
The Glazers, who also own the NFL's Tampa Bay Buccaneers, have declined to engage with fans since buying United in 2005 in a leveraged takeover that loaded debt onto the club.
"Get out of our club," fans chanted as flares were set off. "We want Glazers out."
Fans are currently unable to attend games due to the pandemic but they found a way into the stadium. They also climbed onto vantage points next to turnstile entrances
Supporters wore green-and-gold scarves and also set off flares in the colors of the club's 1878 formation. More than 100 fans got inside the stadium and some could be seen from windows waving down to protesters. Corner flags were held aloft and one supporter was seen throwing a tripod from the interview zone.
Police on horseback later cleared protesting fans from outside the stadium, with glass bottles being thrown in brief clashes. Some fans moved back to a main road near the stadium with police forming a line to stop them returning.
If United had lost the planned game, Manchester City would have won the Premier League title. United is the record 20-time English champion but hasn't lifted the trophy since 2013.
United and Liverpool were among six Premier League clubs that tried to form an exclusive European Super League along with three clubs each from Spain and Italy. Widespread opposition quickly ended the project, with all six English teams backing out within 48 hours of the announcement.
The "Big 6" clubs have been in damage control since, offering various forms of apologies and statements of regret, while fans long frustrated with billionaire owners have called for wholesale changes.