Manchester United chief Richard Arnold says he understands fans' frustrations after a disastrous season but hopes the arrival of new manager Erik ten Hag will lead to "renewed optimism".

Supporters vented their anger against United's unpopular American owners during matches at Old Trafford as their team's woeful campaign fizzled out.

United, who last won major silverware in 2017, finished sixth in the Premier League with their lowest points total since the league was launched in 1992.

Fans have been protesting against the Glazers since they bought the club in 2005, with supporters still concerned about the debt that was loaded onto the club as a result of the takeover 17 years ago.

They were furious about the involvement of the owners in plans to launch a European Super League.

A match against Liverpool in May last year was postponed after protesters broke into the stadium and invaded the pitch at a fixture that was designated to be played behind closed doors due to the Covid-19 pandemic.

There has been a greater level of engagement with supporters over the past few months, and United executive co-chairman Joel Glazer has attended meetings of the fans' advisory board, yet the protests have persisted.

Arnold told a supporters' forum last month that everyone at the club accepted that performances had been below par but said the club was taking "decisive action".

"We are very aware of how fans are feeling and understand their concerns and frustration," he said in minutes of the forum published on Thursday, the same day as United released their latest financial results.

"Football is a game of passion and we fully respect fans' right to make their feelings known, as long as this remains legal and peaceful at all times."

Arnold said he hoped the recent recruitment of Ten Hag from Ajax would allow supporters to approach next season with "renewed optimism".

Football director John Murtough, speaking at the same forum, said the appointment gave everyone at United "clarity and confidence" heading into the new campaign.

United reported an almost 30 percent increase in revenue in their third-quarter results compared with the same period last year.

The Red Devils' total revenue for the three months ending March 31 of this year was £152.8 million ($192 million). Matchday revenues were up sharply after the return of crowds following the coronavirus shutdown

The club's net debt was £495.7 million, up nearly 12 percent.