People who post racist abuse on social media “hide behind fake identities”, said Manchester United manager Ole Gunnar Solskjaer after striker Marcus Rashford was targeted.
The England forward, 21, was abused after missing a penalty in Saturday's shock 2-1 home loss to Crystal Palace.
United's Paul Pogba was also targeted after a spot-kick miss on Monday.
Anti-discrimination body Kick It Out called the abuse “vile” and said “decisive action” needs to be taken.
Earlier this week, Twitter said it will meet any stakeholders to show the “proactive work” being done to tackle abuse after 26-year-old France midfielder Pogba was targeted following a missed penalty in a 1-1 draw at Wolves.
Several of Pogba's team-mates – including Rashford – criticised the abuse, while England women's manager Phil Neville called for footballers to “boycott” social media.
Rashford joins a growing list of footballers who have suffered racist abuse after penalty misses, with Chelsea's Tammy Abraham and Yakou Meite of Reading also targeted this week.
In a statement on Saturday, Kick It Out said: “The vile racist abuse on social media continued today.
“This problem will not go away and needs decisive action – that is what we will be making clear to Twitter when we meet.”
Speaking before United's Premier League defeat by Palace at Old Trafford, Solskjaer called for “authorities to do something” about the problem.
In a news conference after the game, he said: “It's unheard of and we need it to stop.
“I'm just lost for words if it keeps going. We keep having all these campaigns ‘No to Racism' and it keeps hiding behind fake identities. It's just crazy that we talk about this in 2019.”