Manchester United have called on social media giants to step up efforts to banish racist abuse from their platforms after Anthony Martial and Axel Tuanzebe were targeted.
The United players received racist messages on Twitter and Instagram after United's 2-1 home defeat to Sheffield United on Wednesday.
Captain Harry Maguire said the club "will not tolerate" such behaviour.
In a statement, United said: "Everyone at Manchester United is disgusted by the racial abuse received by players via social media after last night's game.
"We utterly condemn it and it is encouraging to see other fans condemn this on social media also.
"Manchester United has zero tolerance of any form of racism or discrimination and a long-standing commitment to campaigning against it through our All Red All Equal initiative.
"Identifying these anonymous mindless idiots remains problematic. We urge social media platforms and regulatory authorities to strengthen measures to prevent this kind of behaviour."
The Professional Footballers' Association (PFA) revealed research in October that showed racist messages to players are disturbingly commonplace.
Of the sample of Premier League players it looked at in its study, the PFA said 43 per cent experienced online "targeted and explicitly racist abuse".
Speaking at the time about the findings of that research, Manchester City and England forward Raheem Sterling said social media operators must "show real leadership and take proper action in tackling online abuse".
Sterling added: "The technology is there to make a difference, but I’m increasingly questioning if there is the will."