Tottenham Hotspur fans have been attacked in a bar in the French city of Lyon on the eve of their side's Europa League tie.
Three supporters were taken to hospital on Wednesday after men wearing balaclavas smashed the Smoking Dog Pub's windows.
The fans have since been discharged.
Lyon-based journalist Alexander Aucott said the windows were smashed with tables and chairs from another bar.
The Foreign Office confirmed it was looking into reports of the attack.
Other fans were hurt by flying glass in the incident that took place nearly 24 hours before the match, in the last-32 stage of the tournament.
Police in Lyon said they believed a far-right group was responsible.
Tottenham won the first-leg of the tie 2-1 at their White Hart Lane ground last Thursday.
Sports journalist Christian Radnedge, a Tottenham fan, who was in the bar - an English-style pub - told BBC Radio 5 live the men gave Nazi salutes before launching the attack.
He said he did not believe the men were Lyon fans.
Among other things, a lit flare is understood to have been thrown into the bar, which was filled with up to 150 fans, landlord Dave Eales, originally from Nottinghamshire, said.
"The front of the pub, which is made up of reinforced glass, was attacked by 20 to 25 people," he said.
"They threw projectiles through the windows. There was a stand-off. They didn't get into the bar. Then it calmed down.
"[But] then they came back a second time and it all started again. There were three injured Tottenham fans taken away by ambulance.
"One of them had a head injury. I'm not sure how bad it was."
Liam Kerwin who was working at the pub said the flare was put out when it landed in a pool of beer.
"Thank God for beer sometimes," he said.
He said the group had chanted: "Jew, Jew."
Katrina Law, a Spurs fan from Wimbledon who was in the bar, said there was a "massive surge" of people and the sound of smashing glass.
She added: "The people that stormed into the bar are not Lyon fans - we hear they were from a far right group."
A club spokesman said a group of about 50 people had confronted fans.
"The situation was dealt with and arrests were made within the hour. Three fans sustained minor injuries and received prompt medical assistance," he added.
Labour MP for Tottenham David Lammy has called for a review of security surrounding fans, particularly when they are travelling in Europe.
He said: "We need to be sure that clubs like Spurs which are inclusive are not now subjected to attacks in this way."