Russia fans stormed past stewards to clash with England supporters at the Stade Velodrome in Marseille on Saturday following the final whistle of their 1-1 draw in their opening game of the European Championship.

A large group of Russian fans in a stand behind England’s goal advanced on the neighboring England section, throwing objects and breaking through a line of stewards, who were outnumbered and offered little resistance.

England fans quickly fled for the exits as Russia fans gave chase and snatched English flags that had been on display.

Governing body UEFA said it will open disciplinary proceedings over the violence at the stadium, with Russia facing stronger sanctions.

When UEFA’s disciplinary panel judges the latest incident, it could take into account Russian fans’ track record of violence, including at Euro 2012, when stadium security staff were attacked in Poland.

The Russian fans were kept behind in the stadium while most England fans left, but were soon allowed to leave the stand. The situation was calmer outside the stadium as a heavy police presence watched over departing fans.

In addition to the confrontations between rival sets of fans, fireworks were set off inside the stadium, raising questions about security; the fireworks should not have been allowed inside the ground.

Two large white flares were set off in the Russian end of the ground, while fireworks were also let off, with a large bang heard from behind the goal defended by England’s Joe Hart.

Shortly before the final whistle, Russia fans also appeared to seize a power cable running around the front of the stand.

Russian football officials downplayed the incident, saying its scale had been exaggerated.

The incident came after a third day of violence in the Mediterranean port city left as many as 20 England fans injured, with reportedly several seriously hurt in bloody clashes between rival fans.

French police had used water cannons and tear gas on rioters hours before the game started.

Fist fights and bottle throwing broke out between the England supporters and their Russian and French counterparts in Marseille’s Old Port on Saturday afternoon.

Rebekah Vardy, the wife of England striker Jamie Vardy, wrote on Twitter that she was subjected to tear gas before kick off, though it was unclear whether it occurred within the stadium.

“That has to be up there with the worst experience EVER at an away game! Teargassed for no reason, caged and treated like animals! Shocking!,” she wrote. “I witnessed this with my own eyes! I can’t comment on things I didn’t see but what I got caught up in was horrific and uncalled for!

Before the game started, England fan Michael Tashall told Press Association: “We were in the Old Port town and the Russian ultras ganged up with the Marseille ultras and attacked the English supporters that were sitting there drinking beers.

“You go into town now and there are English supporters with blood pouring from their head from the Russians’ attacks. They are outrageous. The World Cup in Russia should be taken away from them. It is an outrage.”

Russian Sports Minister Vitaly Mutko spoke to The Associated Press as he left the stadium in Marseille, saying there were no comparisons between the violence in southern France and the 2018 World Cup.

“What’s the 2018 World Cup got to do with it?” said Mutko, who is also the head of the Russian Football Union and has senior roles in FIFA and with World Cup organisation.

World Cup organising committee CEO Alexei Sorokin told reporters: “The World Cup is in two years, this is a different tournament.”

England’s Football Association called on fans “to act in a respectful manner and support England the right way.”

FA spokesman Mark Whittle said, “The FA is very disappointed by the terrible scenes that we saw there and of course condemns such behaviour.”

He called on French authorities “to identify those involved in the troubles and deal with them appropriately and quickly.”

England coach Roy Hodgson declined to comment in detail on the incidents, but said the players “weren’t particularly aware [of what happened] and it certainly had no effect on our preparation for the game and our performance in the game.”

Russia coach Leonid Slutsky also did not comment on the incident while also denying any charge relating to the trouble in Poland at Euro 2012.

Information from The Associated Press and Press Association was used in this report.