Uefa is to investigate alleged racist abuse directed towards England's Ashley Young by some Bulgaria fans during Friday's Euro 2012 qualifier in Sofia.
A spokesman said: "Uefa are aware of the situation. We will study the reports, including the delegate's report, on Monday."
Winger Theo Walcott said the abuse was "very clear" to hear but "ignored it".
Young, who signed for Manchester United during the summer, played an hour before being replaced by James Milner.
Winger Theo Walcott confirmed he had heard what went on the Vasil Levski Stadium but did his best to block it out.
"I was aware. It was very clear," said the Arsenal player.
"I ignored it, but that is me. I think the FA will deal with that and I don't want to comment. The result tonight was the important thing."
Striker Wayne Rooney, who scored twice to add to defender Gary Cahill's opener, added: "As players we could hear it on the pitch. It has been going on for years and it is not right. It needs to stop and hopefully something will be done about it."
England manager Fabio Capello said he had missed the abuse.
"I didn't hear it. I was focused on the game," the Italian said.
But Bulgarian counterpart Lothar Matthaus apologised for the conduct of the minority of his team's fans.
He admitted to being "not very informed" about what had occurred as he had been concentrating on the match.
"But it is very pitiful for such things to happen," the German said at a post-match press conference. "Because of that I would like to apologise on behalf of the Bulgarian Football Federation."
It is not the first time England players have been targeted while on international duty.
In 2008, the Croatian Football Federation was fined £15,000 for racist behaviour shown by their fans towards England striker Emile Heskey during a World Cup qualifier.
Heskey was previously racially abused while on England duty in Slovakia in 2002, while Shaun Wright-Phillips and Ashley Cole were subjected to monkey chants in a friendly against Spain in Madrid in 2004.