Five more Bulgarian football fans were detained for taking part in racist abuse at a Euro 2020 qualifier against England that sparked a storm of protest, the interior ministry announced Friday.
Monkey chants and apparent Nazi salutes during Monday's match in Sofia overshadowed England's 6-0 win, sparking indignation in the football world and leading to the resignation of Bulgaria's football chief.
Police have now identified 16 people suspected of being involved in the racist abuse, the ministry said.
"Five more men implicated in the abusive actions were detained this morning... Police continues work to track down five more to detain them," the ministry said.
A Bulgarian teenager was already indicted Wednesday for "grave hooliganism", risking a jail sentence of up to five years, while five others, including one who is underage, were handed fines and bans from sports events.
Monday's game was halted twice during the first half due to the abuse but England players decided to complete the match instead of walking off the pitch.
British Prime Minister Boris Johnson and his Bulgarian counterpart Boyko Borisov alike condemned the incident.
Under pressure from Borisov, Bulgaria's football federation chief Borislav Mihaylov tendered his resignation, which will be discussed at an executive committee meeting of the organisation later Friday.
Bulgaria's national team coach Krasimir Balakov, who also came under fire for his squad's poor performance, has issued an apology to England fans.
Uefa has opened disciplinary procedures against both Bulgaria and England for their fans' behaviour during the game.
Fifa president Gianni Infantino also pressed Thursday for a worldwide ban on spectators who abuse black footballers.
A total of 48 football fans have been subjected to one or two year bans from attending sports events in Bulgaria and abroad, fines and community work since the beginning of this year, the EU member's police statistics show.