Euro 2016: FA has 'serious concerns' over Lille security
There are "serious concerns" about security in Lille, where England and Russia fans are set to gather for this week's Euro 2016 matches, Football Association chairman Greg Dyke says.
England fans are due to be in Lille ahead of Thursday's match against Wales in nearby Lens, while Russia play Slovakia in the city on Wednesday.
Six England fans were jailed after the teams drew 1-1 on Saturday.
Russia has received a suspended disqualification from the tournament.
The country was also fined 150,000 euros (£119,000) over crowd trouble at the match in Marseille.
Uefa said the punishment would be imposed if similar incidents happen at any of Russia's remaining matches.
Meanwhile, Home Secretary Theresa May described the violence as "deeply disturbing" and said the UK was offering support with investigations and "post-incident analysis".
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Both Russia and England could face expulsion by Uefa, the organisers of Euro 2016, if there is any further violence.
But in a letter to Uefa in response, Mr Dyke rejected the suggestion that England fans were at fault for scenes inside the Stade Velodrome following the match with Russia.
He said that the implication that English fans were in part responsible was "contradicted both by the video evidence and by the fact your independent disciplinary bodies have only instigated sanctions against the Russian Football Union".
England fans, particularly those without match tickets, had been advised to stay in Lille because Lens is a small city, Mr Dyke said.
"We have serious concerns around the security arrangements for the city in the next few days," he added.
"These concerns are heightened with the knowledge that Russia will play in Lille on Wednesday afternoon."
Thousands of supporters are expected to follow Thursday's match between Wales and England at fan zones in the Place Jean Jaures in Lens and also Lille, which is 24 miles (39km) away.
More than 35,000 ticket holders are due to watch the clash in the Stade Bollaert-Delelis.
Responding to an urgent Commons question from shadow home secretary Andy Burnham, Mrs May said the UK was sending police spotters - officers trained to spot trouble-makers at football matches - to support French authorities.
This will involve the deployment of additional British Transport Police officers on rail services in the area, following a request from the French.
She also said 1,400 passports were seized from England fans before the tournament began.
England fans without tickets were being advised against travelling to Lens and Lille, she added.
In other developments:
- Some 35 people have been injured - four seriously, and most of them England fans - and a total of 20 people have been arrested after three days of disorder in Marseille
- Andrew Bache, from Portsmouth, is in a coma with severe brain injuries after being attacked in France ahead of Saturday's match
- Five England fans have been jailed for throwing bottles at police, and one more in connection with other violence
- One England fan involved in disorder in Marseille has been handed a five-year football ban
- Two Russians have been arrested, both for a pitch invasion
- In a separate incident, a Northern Ireland football fan died after falling from a promenade in Nice following the team's 1-0 defeat by Poland
- Wales fans without tickets for Thursday's match against England have been urged not to travel to host city Lens or nearby Lille
Chris Booth, father of jailed England fan Alexander Booth, said his son had thrown "absolutely nothing" and that his sentence was "a joke, it's pathetic".
The clashes in Marseille's Stade Velodrome on Saturday followed England's 1-1 Euro 2016 draw with Russia, after Russian fans appeared to rush at England supporters.
Witnesses said trouble began in the stadium after flares were let off by Russian fans near the end of the game. Some then climbed across barriers designed to keep rival fans apart, and a number appeared to attack fleeing England fans.
The charges against Russia are for crowd disturbances, racist behaviour, and setting off fireworks during the game.
Groups of Russian fans are also being deported from France, with prosecutors saying 150 Russian hooligans were behind the violence in Marseille.
Former head of the National Counter Terrorism Security office, Chris Phillips, told BBC Radio 5 live French police had a "very difficult job" as they were operating under the threat of terrorism, but had "not learned from many years of experience... around dealing with disorder and dealing with crowds of people".
Dr Joel Rookwood, from Southampton Solent University, told the BBC that, to many Russian fans, England "represented the ultimate enemy" and was seen as the inventor of football hooliganism.
Meanwhile, England manager Roy Hodgson and captain Wayne Rooney appealed directly to fans to "behave themselves".