Eye-witnesses have described “horrific” and “disgusting” scenes in Glasgow’s Merchant City on Sunday evening after clashes left two men aged 29 and 30 seriously injured and a 47 year old man in a critical condition in Glasgow Royal Infirmary.

The three men needed hospital treatment after the incident which took place in front of shocked onlookers including families with children celebrating Mothers’ Day in local restaurants.

Police confirmed they were investigating the attack on the 47 year old as attempted murder, and treating the attacks on the two other men as serious assaults. However they said it was too early to say whether the incident at 5pm was linked to the Old Firm match between Celtic and Rangers earlier in the afternoon.

Eye witnesses reported as many as two dozen people were involved in a disturbance near the Strathduie Bar, in Blackfriars Street, with unconfirmed reports claiming the victims, including one man who was stabbed in the neck, were Celtic fans.

One witness, who was dining at The Italian Cafe restaurant, told the Evening Times: “As horrific as it was for an adult, it was even more so happening in broad daylight in front of children.” Some were screaming and upset she added.

“In the end, there were probably about 20 to 25 people fighting in the street, some late teens up to some older guys. There was nowhere else to look - it was literally right outside the windows. We obviously saw the chap who was stabbed in the neck - it happened right at the front of the restaurant.”

“Literally everybody was punching everybody, there were a couple people knocked out.”

One of the victims had been punched and kicked and fell against the wall of a block of flats, she said. But it became clear the attackers were landing more than punches.

“Another young guy came over and, from that distance, it just looked like he was being punched - but then obviously there was just loads of blood, and then it was quite clear that it was more than just a punch. There was actually a doctor in the restaurant who went out to help whilst it was still going on.”

The men then ran up Blackfriars Street where another two people were allegedly injured, the witness added.

Police are appealing for anyone who witnessed the incident or who may have footage to get in touch.

Detective Inspector Peter Crombie of Police Scotland’s Major Investigations Team, said: “There may have been more people injured in this incident who did not seek medical treatment last night and we would appeal for them to come forward and speak to us. We also know that there were a number of people in the area who may have got caught up in it, or stopped to see what was going on. We would ask these people to check back and see if they have any mobile phone footage or images that can help us.”

Neighbouring Albion Street was closed off and traffic diverted from the scene on Friday evening as police investigations continued.

A number of Merchant City businesses, including Bar Soba and Bar Gandolfi, closed early. One local bartender, who did not wish to be shamed, said he had witnessed the aftermath of the incident.

“We closed around four hours earlier than we were supposed to for the safety of our staff,” he said. “I went out for a cigarette about 5.15pm and I noticed two ambulances and loads of police. There was one guy lying propped up against the wall, his face covered in blood, and the entire wall was decorated in blood.

“It was barbaric. I saw him being taken away on a stretcher and his friends were trying to get to him. He was conscious but he had a towel against his neck.” The victim was not wearing football colours, he said, but added: “Another guy who was carted away in an ambulance did have a football top on. It did look like a football crowd.”

Another local restaurant worker said he was screamed at by football fans throughout the day when he refused to serve them booze. He said: I’d been shouted at in the face by football fans because I had to cut them off for being too drunk. It’s a shocking thing to happen on Mother’s Day and makes you scared to come into work when there’s an Old Firm game on.”

Footage also emerged on social media of hooligans throwing chairs through the windows of the Toby Jug pub on Hope Street.

MSP James Dornan said football clubs should be forced to take responsibility for the actions of their supporters. He said the approach known as ‘Strict Liability’ may not have avoided the violence which flared in Glasgow city centre within hours of the final whistle, because it is restricted to the confines of the stadium where a game is being played. But the SNP Member for Glasgow South West said that fans might behave in a different manner if they knew that their actions could have as detrimental impact on their favourite club. He said: “Strict Liability changes the whole match day atmosphere and possibly makes fans think twice before becoming involved in trouble. Sunday’s scenes were shameful. It hardly shows Scottish football in a positive light.”

A Scottish Government spokesman said “We are aware of the disturbance which took place following yesterday’s Celtic and Rangers fixture. There is no place for violence or disorder of any kind in football. However, as a police investigation is still ongoing, it would be inappropriate for us to comment in detail.

The attacks happened as police chiefs in England confirmed they plan to copy Scotland’s approach to cutting knife crime. Amid concern over a spate of nearly 50 alleged stabbings in London so far this year, the Metropolitan Police have already set up a Violence Reduction Unit based on Glasgow’s success with using a public health approach to violent crime.

Home Secretary Sajid Javid is backing the public health approach nationally. However, last month his Cabinet colleague Health Secretary Matt Hancock criticised the idea.

He told LBC: “If you try to say it’s a public health issue, that implies it’s nobody’s fault. You have got to start from the point of the perpetrator being brought to justice.”