Glazer's letter on Friday followed the postponement of United's game against Liverpool last Sunday, when thousands of fans blocked access into Old Trafford in an anti-ownership protest that included clashes with police.

Long-running anger against the American owners that began with a 2005 leveraged takeover that loaded debt onto the club reignited when United joined the European Super League, which quickly collapsed under widespread condemnation.

Glazer acknowledged a "need for change" and reiterated his apology for the Super League fiasco.

"Indeed, one of the clearest lessons of the past few weeks is the need for us to become better listeners," wrote Glazer, the club's executive co-chairman and director.

"To highlight some specific points, as one of the few European football clubs listed on the public markets, we believe in the principle of fans owning shares in the club.

"We have previously engaged with the Manchester United Supporters' Trust on fan share ownership and we want to continue and accelerate those discussions, together with provisions to enhance associated fan consultation."

Glazer's letter - to representatives of the club-led fan forum - acknowledged the need for better consultation on important issues.

"We also recognise the importance of fan and football interests being embedded in key decision-making processes at every level of the club, and we are open to constructive discussions on how to reinforce that principle," he wrote.

One long-held complaint of fans is the neglect of Old Trafford.

"We recognise that we will need to significantly increase investment in Old Trafford and our training complex to ensure that the club's facilities remain among the best in Europe," Glazer wrote, promising to consult with fans on the topic.

The Manchester United Supporters' Trust, which boasts more than 200,000 members, responded cautiously to the letter, saying Glazer's commitments could represent "in theory only" a change in the right direction.

"We will, however, determine our position based on the resulting actions rather than these words alone," the trust said in a statement. "We have seen empty words too many times previously."

United fans' protests against the Glazers have been sporadic as United became the record 20-time champions of England.

But their last Premier League title was won in 2013 and since then neighbours Manchester City have become the dominant force in England.

United were among six Premier League clubs that tried to form an exclusive 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.

Australian Associated Press