PARIS (AFP) - Russia has summoned France's ambassador to protest over the arrest of Russian supporters at the Euro 2016 football tournament which has been tarnished by hooligan unrest.
Amid a growing crackdown on violence at the matches, French authorities announced late on Wednesday that six more Russians had been taken into custody, while three other Russians and a Ukrainian were to be deported.
The detention of his country's supporters on a bus in southern France was branded by Russia's Foreign Minister Sergei Lavrov as "absolutely unacceptable."
"The Russian foreign ministry summoned the French Ambassador Jean-Maurice Ripert," the ministry said on Wednesday, warning that "further stoking of anti-Russian sentiments... could significantly aggravate the atmosphere in Russian-French relations."
It accused France of carrying out "discriminatory and indiscriminate measures against Russian citizens".
But France has hit back with Foreign Minister Jean-Marc Ayrault vowing that the arrested fans would be treated fairly.
"Whether they're Russians, British, they will be treated in the same way by French justice. Most of them behave peacefully, with dignity, with a love of the sport," he said during a visit to Germany.
French police swooped on a group of 43 Russian supporters near Marseille on Tuesday and took them into custody over clashes before and during Russia's match against England on Saturday.
"It was an absolutely unacceptable incident when a bus with more than 40 Russian fans was stopped by police," Mr Lavrov said.
French police "demanded that they get off the bus for document and identification checks," he told parliament.
The minister said French authorities had failed to inform the Russian embassy or the consulate in Marseille before intercepting the bus.
The group included far-right sympathiser Alexander Shprygin, who heads the Russian football supporters association.
Mr Lavrov said Russian diplomatic missions in France only learned of the incident from social media after Mr Shprygin and other fans published pictures and updates about their detention.
French police released 11 of the 43 on Wednesday. French officials said the others could be charged or expelled from the country.
Football's European governing body UEFA have told Russia they will be disqualified from the tournament if there is any more crowd trouble in the stadium.
Russian authorities have accused France of failing to curtail clashes between fans in Marseille and have stressed that England supporters were also to blame.
More than 4,000 police were out on the streets of Lille as thousands of Russian and English fans flooded in to see Russia lose to Slovakia 1-2 ahead of the England-Wales match in Lens on Thursday.
Clashes erupted but were quickly quelled by riot squads behind shields, who fired tear gas and flash bombs.
Thirty-six people were arrested and 16 hospitalised with injuries.
Mr Lavrov conceded it was "unacceptable to behave like some of our citizens" but criticised the "provocative" behaviour of England fans.
"We cannot turn a blind eye to the fact that (the French) are trying to ignore the absolutely provocative actions of fans from other countries," he said, apparently referring to England fans.
The French government has made it clear it will take a tough line on all those found guilty of violence.
"All those who took part in the violence (in Marseille), in this street fighting, must be not only identified (but) sent home," spokesman Stephane Le Foll said.
In Marseille, prosecutors believe they have enough proof to charge some of the detained Russian fans with involvement in Saturday's violence.
"We have sufficiently accurate information that at least some of them took part in the unacceptable violence," top local official Adolphe Colrat said.
Six England fans have been jailed for taking part in the trouble.
In Lille, beery English supporters belted out anti-Russian and anti-European songs and kicked footballs over the heads of watching riot police through the day.
Russian fans occasionally squared up to rivals but there was none of the mass fighting that darkened football's reputation in Marseille.
Yuril Shabanov, 14, from the Russian city of Perm, was enjoying the fan zone with his father and two friends who had flown in from Nice.
"I support the Russian team but not what happened in Marseille," he said of the events that led UEFA to place Russia under "suspended disqualification".
England fans said they were reassured by the presence of British police to assist their French colleagues.