UK & World News
Euro 2012: The Tensions Behind The Clashes
When the Polish interior minister said Russia v Poland would be the greatest ever challenge for Warsaw's police, he wasn't exaggerating - and clashes between rival gangs of hooligans were the most violent images of Euro 2012 so far.
Russian fans are fast becoming the most talked about of the tournament - for all the wrong reasons.
Accused of attacking Polish stewards after their 4-1 victory over the Czech Republic, there was a sense that Polish fans would be out for revenge.
A pre-game Russia Day march through the centre of Warsaw was a red rag to a bull. A full compliment of tear gas, water cannon and rubber bullets was used to try to quash warring hooligans.
The tournament draw was unlucky for Russia. If they had drawn to play in Ukraine it would have meant visa-free travel to a far less hostile environment.
Tensions between Russia and Poland go back centuries.
Their long history of troubled relations includes four decades of Soviet Union dominance in Poland.
Communism was finally overthrown in 1989 but the scars remain. They were reopened in the most devastating way two years ago when the Polish president, Lech Kaczynski, was killed in a plane crash.
He was on his way to a memorial for the 20,000 Polish nationals killed by Soviet Forces in 1940.
Even before the first whistle was blown people were bracing themselves for a traumatic Euro 2012.
Talk of organisational meltdowns and racial tensions have yet to be borne out in earnest. There have been post-match scuffles and reports of racist chanting from small groups of fans.
That aside, the tone has been good natured. English fans have praised the warmth of the welcome they've received from a country and its people - who are desperate to impress.
But there are more than two weeks left in which rivalry will be piqued.
What happens next in terms of any violence could be determined by who stays and who goes.
Unlike some of their fans, the Russian team are performing well and are likely to make it through the group stages. Even if Poland doesn't follow suit, the fans will still be here so the potential for similar scenes remains.
There have been suggestions that England's final group stage match against Ukraine could also be a flashpoint. But the mood in Donetsk, the venue for the game, suggests the opposite.
A fiesta spirit filled the fan zone during Ukraine v Sweden as the home nation became the first team to win in Group D.
Some red-and-white faced fans cloaked in St George flags turned out to be Ukrainian. Their hearts were still with their team, but they were expressing excitement that England are playing in their country.
The bulk of Ukrainian fans seem to admire English football, worshipping big-name players like Wayne Rooney and Steven Gerrard.
One young man said: "I can't believe they are all here - in Donetsk! We just want to welcome everyone - but of course we want to beat you too!"
Riot police will be prepared for any trouble, as they are for every match but hopes are high that any hardcore elements will be drowned out by the good will that is undoubtedly felt by the majority.