Bulgaria head coach Krasimir Balakov has apologised after fans subjected England players with racist abuse, including with Nazi salutes and monkey chants.
The Euro 2020 qualifier in Sofia was twice halted due to the vitriol from the home crowd, FA chairman Greg Clarke at full-time describing the game as "one of the most appalling nights I've seen in football."
Balakov said after the game that he "didn't actually hear" any racist abuse, adding there must be apologies if such claims were "proven to be true", prompting further outrage.
European soccer's ruling body Uefa on Tuesday opened disciplinary proceedings against Bulgaria over the racist behaviour and Balakov has now sent apologises to "all those who feel hurt."
"I strongly condemn and reject racism as a norm of conduct that contradicts modern human relations," Balakov said.
"This is a prejudice that comes from the past that must be eradicated forever.
"I want to say something very clear: given that there have been insults on such a basis, I, as a coach of the national team, apologise to the English footballers and all those who feel hurt."
Bulgarian Football Union President Borislav Mihaylov resigned on Tuesday, a few hours after the Balkan country's Prime Minister Boyko Borissov called for the former international goalkeeper to step down.
Mihaylov had previously defended Bulgarian soccer from accusations of racism and criticised England for what he saw as a "fixation" on potential incidents that could raise tension.
Additional reporting by Reuters.
