There has been a rapid increase of online abuse in recent months and United players have been frequently targeted, including midfielder Fred after the FA Cup quarter-final loss to Leicester.
The club have run the ‘All Red All Equal’ anti-discrimination programme since 2016, with the Old Trafford giants now wanting fans to “see red” when such abuse occurs online.
United have set up an online reporting system and are encouraging supporters to report incidents of racism or other hate crimes and speak out when there is discriminatory abuse.
Group managing director Richard Arnold said: “We are proud that players of all ethnicities, religions and nationalities have pulled on the Manchester United jersey over the years.
“We challenge our fans, and indeed fans of every club, to watch this and think about their own favourite memories, their top teams and their most celebrated players.
“How different would those memories be without the diversity of some of the best players in the world who have graced our game and our club?
“Sadly, footballers across the country continue to receive abuse online, seemingly without fear of censure.
“United has been, and always will be, a club for all. We do not believe real fans are racist, and today we call on those fans to join us in the battle against discrimination.
“It is not good enough for us all to sit silently on the sidelines when we see or read racist remarks or behaviour.
“Inaction has a consequence. We must call it out. We must not tolerate it. If you see it or read it – report it.”
United’s reporting system can be used to report online abuse, with the club saying it will work with “the Premier League to escalate any complaints received to the social media platforms and the relevant authorities and calls on the social platforms to act with urgent and tough action against online racists”.
The seat wraps at Old Trafford have been replaced ahead of Sunday’s match against Brighton as part of the launch of ‘See Red’, which includes a thought-provoking video about diversity and history.
Earlier this week, Premier League rivals Arsenal launched an action plan called #StopOnlineAbuse as part of the club’s ‘Arsenal for Everyone’ programme.
United boss Ole Gunnar Solskjaer hopes there is going to be more action from technology companies as momentum for change continues.
“I certainly hope so and this campaign is certainly one that will have an impact and it’ll be seen,” he said.
“I’m very proud that we as a club we keep campaigning and you’ll see at the stadium on Sunday as well that we mean business.
“It’s about time now that action takes over more than words.”