Chelsea and Real Betis violence breaks out as water cannon fired and riot police deployed

Dozens of riot police intervened to separate pumped-up and Real Betis fans near central square in Wroclaw on Thursday. Footage circulating on social media shows a stand-off between the two sets of supporters in the Polish city, with chairs, bottles and flares launched.

Chelsea and Betis will compete in the final on Thursday evening as they bid to round off their respective campaigns with a European trophy. But the build-up to the contest has been marred by violence between fans in Poland's fourth-largest city. Even on Wednesday, the day before the game, .

And the tensions have carried over into Thursday, with authorities firing a water cannon on Chelsea fans and a horde of riot police storming the scene. Local police have confirmed that 28 arrests were made after an altercation in Market Square.

According to , local supermarkets are running out of beer and pubs are short on pint glasses due to fans taking over the city. Around 70,000 fans are estimated to have jetted in, despite Stadion Wroclaw only holding 45,000.

The spillover has led to unsavoury scenes as groups face off on cobbled streets outside bars and restaurants. One video shows a melee breaking out when a fan kicked a flare towards a group of Betis supporters.

Within seconds, flares, chairs and glass bottles were hurled in the opposite direction. A few hooded Betis fans waded through the crossfire to confront the group of fans on the other side of the street.

A cheer erupted from Blues supporters when riot police arrived on the scene and marched their Betis rivals back to create a wedge between the two groups. The ground was littered with shattered glass and toppled chairs by the time they were separated.

Local authorities will be keen to see the animosity die down before the match itself. Polish Prime Minister Donald Tusk spoke out against the violence on Wednesday, saying: "Zero tolerance for violence on our streets!

"I thank the police for their decisive actions against the hooligans in and Betis shirts in Wroclaw. We warn you: if necessary, the police will be even more ruthless today!"

Betis are competing in their first-ever major European final, and are bidding to become the first side to win all three European titles. As well as the trophy, Thursday night's victors will bank just under £6million in prize money.