England football fans have been urged to behave responsibly ahead of their match with Wales at Euro 2016 later.
Police say 37 people were arrested following clashes in Lille on Wednesday – where riot police fired tear gas and charged at hundreds of England fans.
Martin Glenn, chief executive of the FA, said England fans should be aware of the “wider” situation in France, where police are facing terror threats.
Uefa this week threatened to disqualify England if there was any more violence.
In a statement, the tournament organiser said it “regrets the skirmishes” in Lille, but added the police had been “quick to restore order and keep the situation under control”.
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England play Wales in Lens at 14:00 BST.
Thousands of English and Welsh supporters have been staying nearby in the larger city of Lille – where the latest disorder occurred.
Russian and Slovakian supporters have also been in Lille for their game at the city’s Stade Pierre-Mauroy, which took place on Wednesday.
Some English and Russian supporters were detained after scuffles on Wednesday, when hundreds of England fans were surrounded by riot police in the city’s main square.
Later on Wednesday, police fired tear gas to disperse England fans and charged at supporters.
French authorities said officers faced provocation and excessive behaviour by drunken England fans, adding that of the 37 arrests 15 had resulted in detention.
Tear gas was used twice, with 10 grenades fired in total, to disperse supporters.
There were no major problems between England and Russia fans and there was no direct confrontation with police, they added.
At the scene
By James Reevell, BBC News, in Lille
After running confrontations between England fans and French riot police last night, Lille is a far calmer place this morning.
This is helped by abysmal rain, although that has not stopped a couple of hundred fans drinking outside Lille’s main train station – the same place where police first used tear gas yesterday.
Many of the fans are clearly already drunk and God Save the Queen has been ringing around the square. The fans are loud and good-natured at the moment, but there is still a tension you rarely experience watching football in England.
For their part, the French police are relaxed, although fully equipped in riot gear.
They are keeping their distance, but plain-clothes spotters are close to the fans – ready to grab any potential troublemakers.
Last night felt like the police were tired of English anti-social behaviour, the same issue could arise today once English fans start to return from nearby Lens following today’s game.
One thing that last night made clear is that the French police will only tolerate so much.
The BBC’s Ben Brown ,who is in Lille, says Wednesday’s trouble was “not on the same scale as Marseille”, saying the police “wanted to assert their control”.
“Ultimately the riot police lost their patience with England fans and started firing tear gas, pepper spray and acoustic grenades,” he said.
BBC Radio 5 live correspondent Nick Garnett, who is also Lille, says police had herded fans “from bar to bar” and “when the fans drank the bar dry they moved them on”.
“That was a game of cat and mouse that lasted right the way through the night. Eventually everyone got tired and frankly bored and went home,” he said.
Wednesday night’s disorder followed clashes between mainly English, Russian and French fans in Marseilles at the weekend, which resulted in the Russian football team being given a suspended disqualification from the tournament.
‘Real security threat’
Speaking to BBC Radio 4’s Today programme, FA chief executive Mr Glenn said Uefa had focused on disorder blamed on Russian fans inside the stadium in Marseille when it issued the teams with the threat of disqualification.
He said the atmosphere between England supporters and French police in Lille on Wednesday had seemed “to change overnight”.
He called on England fans to show “consideration and respect”, pointing to the murder on Monday of two French police officials by a man claiming allegiance to so-called Islamic State (IS).
“The French are trying to deal with a real security threat,” Mr Glenn said.
“Behave responsibly, come and enjoy the game, but just have a think about the wider position.”
He said independent security experts had been in Lille and were due to report back to the FA later.
French authorities said those arrested on Wednesday included six Russians involved in the violence in Marseille.
Another five people were arrested for public drunkenness on a train that was stopped before it got to Lille and then allowed to continue.
Some England fans have accused French police of heavy-handedness.
However, Jonathan Calder, a supported in Lille, said he had experienced “over-zealous chanting, threats and drunken slurs”.
“What I saw last night was sinister. I’ve never been so ashamed to class myself as English or British,” he added.
A drinking ban remains in place in some parts of central Lille and the stadium. However, Mr Calder said he had seen “no evidence” it was working.
Shops selling alcohol in the city closed from 18:00 local time (17:00 BST) on Tuesday and will reopen at 06:00 (05:00 BST) on Friday.
BBC sports editor Dan Roan, who is with the England team, said their concern about disorder would have “intensified” overnight.
England were now “skating on thin ice” in terms of the team’s participation in the tournament and the threat of disqualification will “inevitably” have an effect on the players, our correspondent added.
Injured man ‘opens eyes’
Six England fans, aged 20 to 41, have received jail sentences ranging from one to three months in relation to disorder surrounding the England-Russia game, which finished 1-1 on Saturday.
Meanwhile, an England fan left seriously injured after being attacked by Russian supporters has opened both his eyes, his brother has said.
Andrew Bache, 51, from Portsmouth, suffered a cardiac arrest, extensive brain injuries and a lung infection after being attacked in Marseille.
Mr Bache opened his eyes when his son visited him in hospital, his brother Dean said in a message posted on a fundraising page.
He said Mr Bache was still unconscious but was showing signs of improvement every day.
A far-right leader of a Russian fans’ association is among 20 fans to be deported after Marseille violence.
French prosecutors say around 43 Russian supporters had been detained – adding that three will face trial later and 20 will be expelled from France.
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