FIFA opened proceedings against Serbia's football association after a flag which showed Kosovo as part of their country was allegedly hung in the dressing room when they faced Brazil at the World Cup, the soccer governing body said on Saturday.
The image of the flag with the message "we do not surrender" in Serbian went viral on social media when it was shared by Hajrulla Ceku, Kosovo's minister of culture, youth and sport.
"Disgraceful images from Serbia locker room, displaying hateful, xenophobic and genocidal messages towards Kosova, while exploiting FIFA World Cup platform," Ceku said on Twitter.
"We expect concrete actions from FIFA considering that the Kosovo Football Federation (FFK) is a full FIFA and UEFA member."
Kosovo became a member of UEFA and FIFA in 2016, eight years after the country declared independence from Serbia, which opposed the move.
"The FIFA Disciplinary Committee has opened proceedings against the Football Association of Serbia due to a flag displayed in their dressing room on the occasion of the Brazil v Serbia," it said in a statement.
"The proceedings were opened on the basis of article 11 of the FIFA Disciplinary Code and article 4 of the Regulations for the FIFA World Cup 2022."
The FFK said it strongly condemned the "aggressive action" against the country.
"The World Cup is an event of joy and unity and should send messages of hope and peace, not messages of hatred. We call FIFA to take action against such actions," they said.
Serbia, who lost 2-0 to Brazil, next play Cameroon on Monday. Their football federation (FSS) did not respond when asked for comment.
Since Kosovo was made a member of FIFA and UEFA, the European soccer body has ensured for security reasons that its national teams cannot be drawn with Serbia or Bosnia-Herzegovina in qualifying groups for the World Cup and European Championship.
The issue of Kosovo's independence sparked a 1998-99 war in which about 13,000 people died. Serbia launched a brutal crackdown to curb a separatist rebellion by the territory's ethnic Albanians. NATO bombed Serbia in 1999 to end the war.
Kosovo unilaterally broke away from Serbia in 2008. The Serbian government, with support from China and Russia, has refused to acknowledge Kosovo's statehood. The United States and most of its European allies recognize Kosovo as an independent country.
Information from the Associated Press was used in this report.