Some 30 hooded Ukrainians with knives are reported to have set upon England fans in a Kiev coffee shop ahead of tomorrow's World Cup qualifier.
According to reports three Britons were taken to hospital following the incident last night.
One man stabbed, another was treated for a head injury and a third was hospitalised with bruising.
Two of the men have since been released from hospital.
Amateur video footage of the incident appeared to show one of the injured men lying on the blood-spattered pavement as police and ambulances arrived on the scene.
Police in Kiev said the fight involved around “40 English fans and more than 20 Ukrainians” and it broke out after the two sides traded insults.
“Three British citizens ... were taken to hospital with wounds to the head and hands. After getting medical treatment they were taken back to their accommodation,” a police spokesman said.
A Foreign Office spokesman said: "We are aware of incidents in Kiev involving British nationals.
"We are providing consular assistance."
England will take on their Ukrainian opponents in Kiev's Olympic Stadium tomorrow.
They are currently top of their group after beating Moldova on Friday 4-0.
A win against the Ukraine would move them to within touching distance of a place in next summer's finals in Brazil.