Two men from Rome arrested on suspicion of attempted murder following the incident
An Irishman is in a critical condition after being assaulted near Anfield before the Champions League semi-final on Tuesday night.
Two men from Rome, aged 25 and 26, have been arrested on suspicion of attempted murder, Merseyside Police said in a statement.
The Irishman, who is 53 and reported to be in Liverpool with his brother, was seriously assaulted outside the Albert pub at around 7.35pm.
Paramedics arrived at the scene and treated the victim, who suffered a head injury.
He was then taken to Walton Neurological Centre where his condition is described as critical.
Police later entered the ground and arrested two men inside the stadium during the game.
Officers investigating are particularly keen to speak to anyone who witnessed the incident.
Forensic examinations have been carried out at the scene and CCTV footage from the area is being reviewed.
Liverpool Football Club said it was "shocked and appalled" by the incident and urged fans and those who attended the game to help Merseyside Police with their appeal for information.
Detective Inspector Paul Speight said: “We believe the victim, was in Liverpool with his brother, for the Liverpool v Roma semi-final and was assaulted during an altercation between Roma and Liverpool fans near to the Albert pub at about 7.35pm.
“Witnesses report that the victim was hit with a belt and then fell to the ground. Paramedics treated him at the scene and he was taken by ambulance to Walton Neurological Centre, where he is being treated for a head injury. His condition is currently described as critical and his next of kin have been informed.
“The place where this incident occurred is right by the ground and was heaving with fans making their way to the game. I would appeal to anyone who has any information, or mobile phone footage of the incident to contact us urgently, as information they have could be vital to our investigation.”
The two men arrested have been taken to a police station where they will be questioned by detectives.
The Liverpool fan's alleged assailants were among a total of nine men, aged between 20 and 43, who were arrested for various offences before and after the match.
The offences included affray, assault, possession of offensive weapons, possession of a controlled drug, criminal damage and being drunk and disorderly.
Detectives are also investigating the use of flares outside the ground, the force said.
Merseyside Police Chief Superintendent Dave Charnock, said "a number of those in the crowd that had gathered to greet the Liverpool team coach were in possession of flares and work is ongoing to identify those responsible".
He added: "The vast majority of the 52,500 fans attending the game were well behaved and went to watch a good game of football.
"However, a minority of fans from both Liverpool and Roma were involved in isolated pockets of disorder in the city centre and near to the ground."
Anyone with information or mobile phone footage of the disorder was urged to contact police.
Mr Charnock said: "We will be reviewing CCTV footage, our own body worn camera footage and working with the club to identify those involved in any of these incidents so we can put them before the courts.
"And I would appeal to anyone who has any information, or mobile phone footage, in relation to any of these incidents to contact us.
"Finally, I would like to thank the Liverpool Football Club stewards and the police officers who were out on the ground tonight for their hard work and professionalism throughout the evening."
In a statement, Liverpool FC said: "(We are) shocked and appalled after a Liverpool supporter was left in a critical condition having been attacked prior to the Champions League fixture against AS Roma.
"Our thoughts, in the first instance, are with the victim and his family at this very traumatic time. We will be offering them our full support.
"The club has been liaising with the emergency services since the incident occurred and will continue to do so.
"Liverpool FC directs supporters and those in attendance at the game to Merseyside Police's appeal for information."
Anyone with information is asked to contact the Merseyside Police social media desk via twitter @MerPolCC or Facebook Merseyside Police CC.
You can also call the independent charity Crimestoppers anonymously, on 0800 555 111 or via their online form at: https://crimestoppers-uk.org/give-information/give-information.