The 53-year-old was in charge of the team in the 6-0 defeat to England in their Euro 2020 qualifier in Sofia on Monday night which was marred by racist chanting and Nazi salutes from home supporters.

The Bulgarian Football Union executive committee held a press conference on Friday afternoon and it was reported that Balakov, along with the entire committee, had tendered their resignations.

No one from the BFU was immediately available to confirm the news.

Balakov claimed he could not hear any of the racist abuse directed at England's black players during the match.

Step one of UEFA's anti-racism protocol was activated just before the half-hour mark, with the referee asking for a public address announcement to be made ordering the abuse to stop. However, it continued throughout the remainder of the match.

Balakov said on Monday night: "I was concentrated on the game.

"I didn't actually hear anything but I just talked to the English press downstairs and I told them that if this is proven to be true, then we have to be ashamed and we have to apologise for it.

"But, once again, first it has to be proven to be true."

He later issued a statement making a "sincere apology" to the England team and anyone else offended by the racist abuse.

Five more men have been arrested over the events of Monday night.

The five men were detained at the First District police station in Sofia while a further five were searched at a different precinct in the Bulgarian capital, taking the total number identified to 16, a spokeswoman for the ministry of the interior told the PA news agency.

Six supporters were arrested on Wednesday, with four already having been banned from attending any sporting event for the next two years and fined 1,000 lev (A$830). One individual faces a pre-trial hearing on Friday and could be remanded in custody.

The ministry spokeswoman said the search to identify further individuals continues.

England's black players were targeted for racial abuse throughout the match.

The referee initiated the first step of UEFA's anti-racism protocol just before the half-hour mark by asking for a public address announcement in the stadium ordering the racist behaviour to stop.

The abuse continued and although there was a short stoppage just before half-time, the game was completed with England winning 6-0.

Australian Associated Press