England's Euro 2020 qualifier against Bulgaria in Sofia was twice halted before half-time due to racist abuse directed at the England players.
England captain Harry Kane spoke to referee Ivan Bebek after 28 minutes of the first half, as per part one of UEFA's three-step protocol. The second step would lead the referee to suspend the match for a period of time and the third would be to abandon the match.
The game, which England won 6-0, was stopped for a PA announcement before play resumed. But after the abuse continued, England boss Gareth Southgate spoke to the fourth official and the match was briefly halted for a second time shortly before half-time.
After the game, the FA released said in a statement: "The FA can confirm that England players were subjected to abhorrent racist chanting while playing in the EURO 2020 qualifier against Bulgaria.
"This is unacceptable at any level of the game and our immediate focus is supporting the players and staff involved.
"As we are sadly aware, 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 behaviour in society, let alone in football.
"We will be asking UEFA to investigate as a matter of urgency."
Sky Sports News' Rob Dorsett reported hearing 'clear monkey chants' on six separate occasions during a 10-minute period during the first half when Tyrone Mings and Marcus Rashford had possession of the ball.
"I heard one fan clearly shout 'Hey, monkey' as Rashford passed the ball," reported Dorsett.
England's Raheem Sterling took to social media after the game to express his views: "Feeling sorry for Bulgaria to be represented by such idiots in their stadium.
"Anyway.. 6-0 and we go back home, at least we did our job. Safe travel to our fans, u guys did well."
Marcus Rashford also took to social media to voice his opinion and also praise the efforts of Ivelin Popov who spoke to the home fans in an attempt to halt the abuse.
England debutant Tyrone Mings expressed his pride at how his team-mates handled the situation: "Very proud moment for me and my family tonight to make my England debut. The unfortunate incidents in the game were handled as well as possible and proud of how we handled it."
Sky Sports News interviewed Steve Graham, Chief Superintendent UK Sport Unit, pitchside during the game.
"It's quite simply the worst racist behaviour I've ever seen from a group of supporters, either at the international or club stage, it is indescribably bad," said Graham.
"We've been seeing songs where they appear to make Nazi salutes during the singing. Whenever Raheem Sterling, in particular, got the ball we were hearing monkey chants and concerted booing.
"Then some other black players, we heard booing that was being overtly directed at those players. During the pause in the game, we saw a flag with right-wing images demonstrated as well."
Sky Sports pundit Roy Keane told ITV: "That was horrible. You feel physically sick hearing that."
According to Sky sources, specialist security officers - who were privately employed, not by the Bulgarian FA - ejected a group of 20-25 "fans" from one of the sets of Bulgarian supporters.
They were dressed all in black, pertaining to be part of a neo-Nazi group, and were seen making Nazi salutes.
The game continued without further interruption after half-time, with England ultimately winning the tie 6-0.
Anti-racism group Kick It Out said in a statement: "We are sickened by the disgusting racist abuse directed at England's men's team tonight by Bulgaria supporters - including TV footage which appeared to show Nazi salutes and monkey noises.
"We applaud Gareth Southgate, his staff and players for the actions taken in reporting the abhorrent abuse, and offer our full support to the entire squad, their families and anyone affected by those appalling scenes.
"We are encouraged that the protocol was initially enforced by the match officials, but UEFA must explain why players weren't sent to the dressing room during Step Two, as is clearly stated in the rules.
"TV footage also clearly shows that racist abuse continued in the second half, so it is unacceptable that Step Three was not enforced. This match should have been abandoned by the officials.
"It's now time for UEFA to step up and show some leadership. For far too long they have consistently failed to take effective action. The fact Bulgaria are already hosting a game with a partial stadium closure for racist abuse shows that UEFA's sanctions are not fit for purpose.
"There can be no more pitiful fines or short stadium bans. If UEFA care at all about tackling discrimination - and if the Equal Game campaign means anything - then points deductions and tournament expulsion must follow."
Bulgaria stadium partially closed after previous abuse
The game was played in a partially closed Vasil Levski National Stadium after UEFA imposed sanctions following incidents during Bulgaria's matches against Kosovo and the Czech Republic in June.
5,000 of the 46,340 seats had to be left empty, although that number will be reduced to 3,000 for the game against Czech Republic next month.
Banners bearing the words 'Equal Game' were displayed across the empty seats at the stadium.
Bulgaria were fined 40,000 Euros in 2011 after fans abused Ashley Young, Ashley Cole and Theo Walcott during a Euro 2012 qualifier.