Fans of the Dinamo Zagreb soccer club displayed a banner with a vulgar and abusive message against Serb women and children at a soccer match held in a Zagreb suburb on Thursday evening, prompting public outrage and a police investigation into the incident.

The banner with the obscene message was raised by spectators on the stands during a match in the Kustosija neighbourhood in western Zagreb, along with a symbol of the WWII fascist Ustasha regime and flags of the Croatian Defence Forces (HOS), a paramilitary branch of the right-wing nationalist HSP party, which was active at the beginning of the 1991-95 war in Croatia.

Interior Minister Davor Bozinovic on Friday condemned the incident and confirmed that a police investigation was launched.

While Prime Minister Plenkovic said he had not seen the photograph of the banner, which was published on Facebook by photographer Nikola Solic Thursday night, he called the incident unacceptable.

“I strongly condemn any messages like that, there is no room for that in public. Without question, this is unacceptable,” Plenkovic told N1.

Head of the Serbian National Council, MP Boris Milosevic, told N1 that the incident was just the latest instance in a worrying trend which is becoming s systemic problem of the society.

“This is horrifying and disturbing to everyone, not just the Serb minority. It’s sad to see that the young people in Zagreb are filled with so much hate that they would write such disgusting messages,” Milosevic said.

Later on Friday, the police reported that four people were brought in for questioning in connection with the incident.