In the wake of recent terror attacks in Europe, French authorities are on high alert, worried that the 2016 EuroCup could be eyed as a potential target.
But in recent days, another source of terror has come to light: Inebriated English and Russian soccer fans.
Hours before Saturday's match in Marseille between the two countries had even started, fans were clashing violently with French riot police, following two nights of unrest on Thursday and Friday.
The French sports minister, Patrick Kanner, told i-Television on Saturday that authorities had pegged the game as "one of the five risky matches" of the entire tournament.
"British and Russians with the heat," Kanner said, "that can be explosive."
The latest bout violence reportedly around 3pm local time. The Guardian reported that around 60 riot police surrounded soccer fans as they drank in bars around the old French harbor. Some fans responded to the advance by lobbing bottles at the police, and the police responded with water cannons and tear gas. Brutal video emerged of the ensuing clashes between soccer fans.
UK police authorities said that they were aware of the clashes, and said that "any British fans who may have been involved will be identified and dealt with accordingly."
Shadow home secretary Andy Burnham described the behavior of England fans as "embarrassing."
When you think of the terror threat & everything the French are dealing with, makes behaviour of these England 'fans' even more embarrassing
— Andy Burnham (@andyburnhammp)June 11, 2016
A BBC correspondent at the "pretty terrifying" scene said bottles were being thrown every couple minutes and police were dragging away bloodied England fans.
French police had to break up small groups of English and Russian fans on Friday who were fighting with one another. Nine people were reportedly arrested, including five who had traveled from the UK.
The game in the Mediterranean port city kicks off at 8:00pm local time in the Stade Velodrome, where about 1,000 police were deployed ahead of the game to greet the 70,000 England fans and 20,000 Russian fans who arrived ahead of the match.
France is still under a state of emergency since the Islamic State launched devastating attacks on Paris last November that killed 130 people.
England will play Wales next Thursday and Slovakia on June 20, in Lens and St. Etienne respectively.
During the 1998 World Cup, England fans were involved in riots in Marseille when they played Tunisia.