SOFIA - A Bulgarian teenager was indicted for "grave hooliganism" while four others were fined and received stadium bans over racist abuse at a Euro 2020 qualifier against England, officials said Thursday.

Monkey chants and apparent Nazi salutes during Monday's match in Sofia sparked a storm of protest that overshadowed England's 6-0 win and led to the resignation of Bulgaria's football chief and.

Thanks to CCTV footage from the national stadium, Sofia police have so far identified nine suspects in the stands, part of a group of black-clad fans, who directed the abuse at England's players. Six of them were detained on Wednesday.

"One 18-year-old was indicted late Wednesday for grave hooliganism and ordered detained in custody for 72 more hours," Sofia regional prosecution spokeswoman Nevena Zartova told AFP.

According to the indictment, the man used obscene hand gestures and Nazi salutes and turned his back to the field and pulled down his trousers twice.

If found guilty, he could face up to five years in jail.

"Out of the other five, four were handed 1,000-leva (511 euro, $568) fines and two-year bans from sports events. Procedures against the fifth, who is underage, are still ongoing," Sofia police directorate spokeswoman Svetoslava Kostadinova said.

The game was halted twice during the first half due to the abuse.

England manager Gareth Southgate told reporters after the game that his side had been ready to walk off the pitch if the abusive behavior continued but players decided to complete the match.

The incident sparked a storm of angry reactions from fans, media and officials in both countries, leading to the resignation of Bulgaria's football federation chief under pressure from the government and apologies from the national team manager.

UEFA called for a war on racist abuse and announced that it was launching a probe into the behavior of both the Bulgaria and England fans. UEFA president Aleksander Ceferin said European football's governing body was determined to root out the "disease" of racism.

Bulgaria has tightened measures against football hooliganism after several incidents in 2018.