Middlesbrough and Everton have condemned "vile and unacceptable" racist online abuse of winger Yannick Bolasie and reiterated a "zero tolerance" approach to discrimination.
Both clubs have offered support to the Toffees player, on loan at Boro, who said the issue was of "great concern".
The messages have been passed on to the authorities by the player and clubs.
"We will not tolerate abuse of any form," Boro's statement said.
"The racial abuse directed to Yannick Bolasie on social media yesterday is vile and unacceptable, and demonstrates exactly why more has to be done to identify the perpetrators of such comments and to bring them to justice.