At least 36 people have been arrested in Lille following clashes between French police and football fans at the Euro 2016 tournament.
French police said the arrests had been made throughout Wednesday – adding that 16 people had been taken to hospital.
On Wednesday night, riot police used tear gas and charged at hundreds of England fans, as flares were set off.
Uefa this week threatened to disqualify England, – who play Wales later – from Euro 2016 if there was more violence.
England play Wales in the nearby city of Lens at 14:00 BST.
- How is French security ensuring fan safety?
- QA: Who is to blame for the violence?
- Russia’s new breed of hooligans
- What do Russian fans say?
- England and Wales fans ‘stick together’
Thousands of the English and Welsh supporters have been staying in the larger city of Lille ahead of the match.
Russian and Slovakian supporters have also been in Lille for their game at the city’s Stade Pierre-Mauroy on Wednesday.
It follows clashes between mainly English, Russian and French fans in Marseilles at the weekend.
The Russian football team was given a suspended disqualification from the tournament following attacks by their supporters on England fans in Marseille.
BBC sports editor Dan Roan, who is with the England team, says concern about the disorder will 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.
At the scene
By James Reevell, BBC News, in Lille
Darkness brought a dramatic escalation in tensions between English fans and French police.
Hundreds of supporters engaged in scuffles with the police, who used tear gas, flash bangs and baton charges to disperse them.
The fears earlier in the day had been of attacks by hardcore Russian hooligans, but this was very much an English problem.
They sang their chant “Please don’t send me home” and threw bottles in challenge at the police.
After funnelling fans down the city’s streets, the police withdrew and some fans were left to stay in the city centre, if in a less boisterous mood.
It’s unclear what caused the situation to escalate, as earlier in the day the police had been happy to contain the fans and keep them separate.
The city was tense, but disturbances were low-key, with running battles quickly stopped by the police.
Now the fear is what will happen when ticketless fans watch the England v Wales game in the city.
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 from London that was stopped before it got to Lille and then allowed to continue.
Earlier, some English and Russian supporters had been detained after scuffles. Hundreds of England fans were surrounded by riot police in the city’s main square.
They were then pushed back into the corner of the square by police in riot gear, before the square was cleared.
England supporter Oliver Larkworthy, from Norwich, is in Lille and was caught up when police fired tear gas at fans at the city’s railway station.
“I saw a massive crowd running down the street – English fans, Slovakian fans and locals mainly, a real mix,” he said.
“There is a massive mob of Russian fans standing outside the station just waiting to cause trouble. The whole thing is a disaster waiting to happen. It’s like a massive tinder box waiting to go off any minute.”
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.
On Wednesday, Russia’s foreign ministry summoned the French ambassador to Moscow, as well as sharply criticised policing at the Euro 2016 tournament.
“Further stoking of anti-Russian sentiments… could significantly aggravate the atmosphere in Russian-French relations,” the ministry said.
Michel Lalande, prefect of the Nord-Pas-de-Calais Picardy region, said a drinking ban was in place in some parts of central Lille and the stadium.
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, he said.
However, the BBC’s Geraint Owen, in Lille, said small supermarkets were still selling alcohol on Wednesday afternoon, and drinking was taking place openly on the streets.
Vince Alm, of the Football Supporters’ Federation Cymru, said the ban was not enforceable. “There are so many outlets around it’s impossible,” he said.
Fans are being discouraged from travelling if they are without a ticket to the England-Wales game, and the authorities have also asked those with tickets to delay travel until the day of the game.
Those without match tickets can watch the match in the city’s fan zone, where lower-strength beer will be sold.
Mr Lalande also said anyone carrying out violence would be removed from the country.
British Transport Police officers travelled with fans on Eurostar trains on Wednesday.
Eurostar is running some alcohol-free services, with no alcohol allowed through check-in or purchased at departure lounges or on board.
Are you in Lille? Have you been affected? You can share your experiences by emailing.
Please include a contact number if you are willing to speak to a BBC journalist. You can also contact us in the following ways: