An England fan was fighting for his life on Saturday after violence broke out on the streets of Marseille for the third day in a row.

The man was reportedly in a critical condition after sustaining a serious head injury in an attack by Russian football hooligans. Paramedics were seen giving the 51-year-old CPR on the pavement but his condition was unknown.

Hundreds of England supporters ran down side streets and fled across the Place General de Gaulle after being charged by lines of riot police firing tear gas, leaving piles of smashed glass and debris on the ground

As the gas dispersed, fans could be heard singing “God Save the Queen” as celebrations to mark the monarch’s 90th birthday continued in the UK.

There were conflicting reports on what caused the crackdown, with witnesses claiming they had seen English, French and Russian men involved in street brawls.

“Marseille and PSG fans are fighting so the police tear gas innocent England fans singing outside a pub, typical,” one witness wrote on Twitter.

Another claimed police attacked England fans for “no reason”, while several French commenters were blaming English tourists for the disorder.

In pictures: Euro 2016 violence in Marseille Show all 12 1 /12 In pictures: Euro 2016 violence in Marseille In pictures: Euro 2016 violence in Marseille An England fan is detained by French security personnel in the city of Marseille, southern France, on June 11, 2016 AFP/Getty Images In pictures: Euro 2016 violence in Marseille English supporters at the Old Port of Marseille, France, 11 June 2016 EPA In pictures: Euro 2016 violence in Marseille An England fan kicks away a tear gas canister after tear gas was released by French police in the city of Marseille, southern France, on June 11, 2016 AFP/Getty In pictures: Euro 2016 violence in Marseille An England fan in clashes with police in Marseille on June 11, 2016 AFP/Getty Images In pictures: Euro 2016 violence in Marseille French police officers charge England fans in Marseille Reuters In pictures: Euro 2016 violence in Marseille England football fans shout as they clash with police in Marseille GETTY In pictures: Euro 2016 violence in Marseille England fans throw bottles at police in Marseille GETTY In pictures: Euro 2016 violence in Marseille A tear gas canister explodes under a football fan as England fans clash with police in Marseille GETTY In pictures: Euro 2016 violence in Marseille French riot police used tear gas to disperse England fans on a second day of clashes GETTY In pictures: Euro 2016 violence in Marseille French police monitor England fans in Marseille Getty In pictures: Euro 2016 violence in Marseille England fans grouped at O'Malley's pub in Marseilles on Thursday night Getty In pictures: Euro 2016 violence in Marseille Trouble flared outside an Irish pub in the Old Port of the southern city of Marseilles just before midnight Thursday AP

Dr Geoff Pearson, a senior lecturer in criminal law at the University of Manchester who is in Marseille, told The Independent England fans were being attacked by groups of Russian “ultras”.

“They are running around looking for bars full of English people and looking for a fight and the police are always a few steps behind,” he said.

“The England fans are very much on the back foot here – they’re getting attacked by Russians, there is no protection from the police and they are continually getting tear gassed. There are quite a few serious injuries.”

Dr Pearson said he had seen small numbers of English tourists throwing bottles but said the police response was “disproportionate” and was increasing tensions between football supporters and security forces.

“The England fans are furious,” he added. “I don’t think it’s going to calm down.”

Other witnesses said women and children were caught up in the violence, with many reporting the presence of a group of around 20 Russian fans attempting to start fights.

Laurent Nunez, the local police commissioner, told the AFP news agency: “Police intervened in a fight between English, Russian and French supporters in the Old Port area.

"It was troubling but calm returned within a few minutes."

But shortly after his comments, violence broke out again with footage showing running fights in side streets between rival groups.

A water cannon and reinforcements were also seen arriving in the area. At least six people had been arrested, local police said.

A man is arrested by police officers in downtown Marseille, France, Saturday, June 11, 2016. (AP)

The mood had been happy earlier in the day, with fans gathering in the French city’s bars and restaurants ahead of the England vs Russia game.

“The atmosphere is good-natured but spirits are already fuelled by alcohol,” La Marseillaise newspaper noted.

Violent clashes have overshadowed the build-up to England's opening game of Euro 2016 over the past two days.

Disturbing footage of the second night of trouble on Friday showed English fans pelting objects into the street, showering the police with bottles and throwing chairs out of cafes.

Flares were also lit as officers deployed tear gas in an effort to disperse the troublemakers throughout the day.

An England fan kicks away a tear gas canister after tear gas was released by French police in the city of Marseille, southern France, on June 11, 2016 (AFP/Getty Images) (AFP/Getty)

Reacting to the violence, shadow Home Secretary Andy Burnham tweeted: “When you think of the terror threat & everything the French are dealing with, makes behaviour of these England 'fans' even more embarrassing.”

He added: “As ever, vast majority let down by a minority.”

Bare-chested England fans sang songs about the IRA and German bombers being shot down as violence first broke out on Friday shortly after 6pm outside the Queen Victoria pub in the Old Port district.

Fist fights broke out between English, French and Russian-speaking men, and one man was thrown into the harbour after he was beaten to the ground by local fans.