The police have been called to investigate claims Yaya Toure was racially abused within hours of reactivating his Twitter account.
Manchester City midfielder Toure rejoined Twitter on Monday, five months after leaving the social network site in order to focus on the World Cup.
The Ivory Coast international posted his first tweet at 6pm, reflecting on City's derby win over Manchester United the previous day.
He wrote: "Great to be back on twitter after a good win yesterday. Now my focus is on the next game... Happy Monday everyone!!"
Within hours of posting the message, the 31-year-old received abusive and racist messages from other Twitter accounts.
Anti-discrimination group Kick It Out was appalled by some of the tweets and decided to report the matter to the police.
"NEWS: We are informing the Police of racist tweets directed @yayatoure earlier this evening and offer him our full support #kickitout," KIO posted on Twitter.
A Kick It Out spokesperson told Press Association Sport on Monday night: "At this stage we have received complaints about two separate tweets of a racist nature aimed at Yaya Toure and now we are informing the police.
"Yaya Toure has been on Twitter for a matter of hours and he has already received abuse of an appalling nature.
"We are disturbed by the fact that someone can be treated this way.
"It makes footballers start to question why they should use these platforms.
"We will offer Yaya Toure our full support."
On Monday evening Toure favourited a tweet from one City fan - @111Lesley111 - who offered her support to the former Barcelona player.
She wrote: "@YayaToure Welcome back to the land of the tweetiverse. Ignore the nasty jealous ones. There are far more out here that (heart) you. #MCFC"
This is not the first time Toure has been the target of racist abuse.
Last season he was subjected to racist chanting during City's Champions League game at CSKA Moscow.
"I'm not just disappointed, I'm furious," Toure said after City's 2-1 win in Russia.
"It was unbelievable and very sad."
CSKA denied Toure had been abused, but UEFA disagreed and ordered the Russian club to close part of their ground for their next Champions League match.