Ukrainian police want to identify and find about 20 Dynamo Kyiv fans as part of an investigation into racist abuse directed at Shakhtar Donetsk player Taison.

The Brazilian midfielder left the field in tears after reacting to the abuse in Sunday's game by showing an obscene gesture and kicking the ball in the direction of Dynamo's fans.

The referee took the players off briefly and then gave Taison a red card for his reaction once the game resumed. World players' union FIFPro and anti-discrimination campaigners have called for that card to be rescinded.

Police in the city of Kharkiv, where Shakhtar plays, said on Tuesday they have opened criminal proceedings on allegations of "violation of citizens' equality" due to race, nationality, religion or disability.

Taison, who has played eight times for Brazil, said on Instagram on Sunday he "will never stay quiet after seeing such an inhuman and despicable act."

The Fare Network, which campaigns against discrimination in soccer, welcomed the police announcement and advised the Ukrainian soccer association to overturn Taison's red card.

"We welcome the police investigation and await the outcomes of action by the criminal justice system in Ukraine. But this should not exempt football authorities from doing their part," Fare spokesman Pavel Klymenko said. "The UAF should immediately rescind the red card given to Taison. And it goes without saying the UAF should apply strong measures against the perpetrators."

FIFPro spokesman Alex Duff said the organization had joined the Ukrainian players' union in writing to the UAF "asking for Taison's red card to be overturned." FIFPro is also asking for an investigation into the fans' behavior and how match officials handled the situation.

FIFPro launched a similar campaign in Italy in 2017 when Ghanaian player Sulley Muntari was red-carded in Italy for walking off the field in protest at racist abuse. The Italian soccer federation overturned a one-game ban for Muntari in that case.

The UAF said Monday it would issue a "fair verdict" on the case but hasn't given a date for a disciplinary committee hearing. The UAF also praised Dynamo players who supported Taison and tried to persuade fans to stop the abuse.