Fighting broke out between Turkish football fans celebrating their team's World Cup victory and a group of Kurdish men, police said.
Two men were arrested during the incident in Harringay, north London and one man was taken to hospital with head injuries.
A Scotland Yard spokesman said police were called to deal with fighting between about 100 Turks and between 40 and 50 Kurdish men.
"Some missiles were thrown between the rival groups," the spokesman added.
Local police and territorial support officers managed to separate them but continued to shout at each other across the police divide, he said.
One man was arrested for public order offences and another was held for assault. They were taken to police stations in north London.
A 25-year-old man was taken to hospital by ambulance suffering head injuries, but his condition was not thought to be life threatening.
Police are trying to move the rival groups away from each other in opposite directions in a bid to stop the fighting.