England’s Euro 2020 qualifier in Bulgaria was halted twice as fans were warned about racist behaviour including Nazi salutes and monkey chanting.
The first pause came in the 28th minute with England leading 2-0.
A stadium announcement then condemned the abuse before stating the match would be abandoned if it continued.
However, the game was stopped again in the 43rd minute before restarting after discussions between the referee and England manager Gareth Southgate.
England went on to win 6-0 in Sofia to strengthen their place at the top of Group A.
Football Association chairman Greg Clarke was at the game and witnessed the abuse first hand, saying it had left a number of the England players and staff visibly upset.
“I heard examples of appalling racist chanting,” he said.
“I was looking at a group of people, all in black – about 50 of them – who were making what looked like political fascist gestures. I couldn’t be sure, it was 100 metres away but it looked appalling.
“I’ve spoken to one or two of the players and I’ve also spoken to one or two of the backroom staff, because we don’t just have a multiracial team, we have a multiracial backroom staff.
“They were visibly emotionally upset, and I spoke to Gareth after the game too and I offered him our full support.”
Clarke says he expects European football’s governing body Uefa to conduct a thorough review of the incident.
“Uefa, who I’ve spoken to throughout the game, at half-time and at the end of the game, will be carrying out a thorough investigation to make sure this appalling scene of terrible racism is treated appropriately,” he said.
In a statement, the FA confirmed England players were subjected to “abhorrent racist chanting” and that it was “unacceptable at any level of the game”.
England defender Tyrone Mings, who was making his international debut, said the players had decided as a group at half-time to continue the game.
“Just before the end of the first half the appropriate next step was to return to the changing room,” he told BBC Radio 5 Live.
“We made a common-sense decision to play the remaining few minutes and decided at half-time. Everybody made the decision. The manager, the team, the supporting staff. We spoke about it at half-time and we dealt with it and escalated it in the right way.
“I am proud of how we dealt with it and took the appropriate steps.”
