The game was stopped in the 28th minute and the 43rd minute because of the actions of the Bulgarian fans, some of whom wore black hooded tops and others bandanas to cover their faces.
After the first break in action, an announcement was made in the stadium that the match could be called off unless the racist abuse stopped, in line with UEFA’s three-step anti-racism protocol.
During the second break, dozens of Bulgarian supporters who had been involved in the monkey chanting left the stadium.
Before the match, Mr. Mihaylov, Bulgaria’s soccer chief, had written to UEFA’s general secretary to complain about comments made by England’s manager, Gareth Southgate, about potential racial abuse that his players could face during the Sofia visit.
Mr. Mihaylov had called the England manager’s claims that his players could face discrimination from spectators “offensive” and “derogatory.”
But Mr. Southgate’s comments were prescient.
“This is not the first time our players have been subjected to this level of abuse and there is no place for this kind of behavior in society, let alone in football,” England’s Football Association said on Twitter after the game, calling on UEFA to investigate the episode.
A spokesman for Prime Minister Boris Johnson of Britain said on Tuesday that the racism England endured during the match was “vile,” and also endorsed the idea that UEFA should conduct an investigation into the matter, “with tough penalties to follow.”