Boris Johnson has joined demands by anti-racism campaigners for Uefa to take strong action after the racist chanting that marred England’s Euro 2020 qualifier against Bulgaria on Monday night.

European football’s governing body has opened disciplinary proceedings against the Bulgarian Football Union (BFU) for racist behaviour of its supporters after the incidents at the Vasil Levski Stadium in Sofia, in which some home fans made monkey noises at Tyrone Mings, Raheem Sterling and Marcus Rashford in the 6-0 victory for Gareth Southgate’s side.

The BFU was also charged over Nazi salutes by fans and the throwing of objects from the stands, while they and the English Football Association (FA) were both charged over the disruption of national anthems. The FA also faces a separate charge of having insufficient travelling stewards.

The match was halted twice during the first half under Uefa’s anti-racism protocols after Mings and Southgate alerted officials about the abuse, with television pictures at half-time also showing several fans using Nazi salutes. Their actions were condemned by the anti-­discrimination groups Kick It Out and Fare, while the FA chairman, Greg Clarke – who is also vice-president of Uefa – called for the authorities to now show “zero tolerance”. The sports minister, Nigel Adams, has ­written to the Uefa president, Aleksander Čeferin, offering support and asking him to take “urgent action” after the prime minister’s spokesman said the incidents were a “stain on football”.

“The England players and management showed tremendous dignity and the prime minister commends the players who were targeted for this ­despicable abuse for their response,” he added. “We support the FA’s calls for an urgent investigation with tough penalties to follow.”

A section of the stadium was closed for Monday’s game after Uefa imposed sanctions over racist incidents during Bulgaria’s qualifiers against Kosovo and the Czech Republic in June.

The punishment will also apply in the home game against the Czech Republic next month. The next step would be to implement a full stadium closure, as was the case with Montenegro after England’s players endured similar racial abuse during the qualifier in Podgorica in March, although Uefa’s disciplinary panel is allowed to go much further and has the power to expel a country from a tournament.

However, Bulgaria is expected to argue that those responsible for the problems were in the minority and dealt with by stadium stewards.

A group of about 50 people, who are understood to have been members of club side Lokomotiv Plovdiv’s “ultras” group Lauta Army, were asked to leave at half-time. Čeferin has defended Uefa’s punishments for racism as “among the toughest in sport” and called on for a “war” on ­discrimination but added that it would require the help of governments and the whole “football family” to tackle the problem.

“Believe me, Uefa is committed to doing everything it can to eliminate this disease from football,” he said. “We cannot afford to be content with this. We must always strive to strengthen our resolve.

“More broadly, the football family– everyone from administrators to players, coaches and fans – needs to work with governments and NGOs to wage war on the racists and to ­marginalise their abhorrent views to the fringes of society.” He added: “Football associations themselves cannot solve this problem. Governments to0 need to do more.”

But Kick It Out demanded that Uefa should consider a points ­deduction or tournament expulsion. “The fines from Uefa we don’t think are enough,” chief executive, Roisin Wood, said on the Today programme. “There have to be serious steps now, and that should include looking at expulsion or not letting people enter ­tournaments, because there has to be a clear message. This is 2019. These are ­professional players going out to play. You would never expect to get this in your workplace so why should ­professional players get it in theirs?”

Gianni Infantino, president of Fifa, the world game’s governing body, said he wanted “all football governing ­bodies to join us and think together of new, stronger and more effective ways to eradicate racism in football”.

He added: “As a starting point, I ­suggest that all competition organisers enact regulations which envisage life bans from stadiums for those who are found guilty of racist behaviour at a football match. Fifa can then enforce such bans at a worldwide level.”

Borislav Mihaylov, the BFU’s president, has resigned after the prime minister, Boyko Borissov, demanded that he stepped down following his comments before the match last week. The former Reading goalkeeper had urged Uefa to take action against ­England after the Chelsea striker, Tammy Abraham, said ­Southgate’s side would walk off the pitch if they heard racist chanting.

“After last night’s shameful defeat and given the bad results our football has registered recently, I’ve told sports minister Krasen Kralev to end all kind of relationships with the BFU, ­including financial ones,” Borissov wrote on his Facebook page. “I also strongly condemn the behaviour of some of the fans that were in the stands. It’s absolutely unacceptable for Bulgaria, which is one of the most tolerant countries in the world [and] where people of different ethnic and religious origins live together in peace, to be associated with racism.”

That reaction was applauded by the Manchester City and England forward Sterling, who was also on the receiving end of racist abuse in Montenegro. “A good move credits to you M. Borissov,” Sterling wrote on Twitter. But the Bulgaria goalkeeper, Plamen Iliev, saw it differently after the match, claiming the home supporters had “behaved well” and that England’s players had “overreacted a bit”.

Yet the Aston Villa defender Mings, who was making his first international appearance on Monday, admitted he had spoken out because he felt a duty to report the abuse.“It didn’t affect my feelings,” he said. “I think I’m quite lucky in that way because I don’t feel like it is a personal assault. I feel sorry for the people who have those views. But I also have a duty to represent people that don’t have a voice. It was important that it was bigger than me, bigger than what I felt.”