Celtic have released a statement after two supporters were stabbed "by Lazio ultras" in Rome.

The two fans have been left needing hospital treatment following the attack by a group of masked thugs outside the Flann O'Brien Irish pub last night.

It comes amid heightened tensions ahead of tonight's second-leg Europa League clash.

It's been reported that a group of armed thugs ambushed the supporters outside the bar shortly after 11.30pm Rome time.

Evening Times: Celtic fans at the Flann O'Brien pubCeltic fans at the Flann O'Brien pub

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A witness, Dennis Connelly from Kilmarnock, told the PA News Agency: "We were just in the pub maybe the back of 11 last night and then maybe 15 or 20 Lazio fans, well I'm assuming Lazio fans, turned up with their masks on.

"They pen-knifed a guy, they stabbed a guy in the leg, now this man's 53 or 55 years old, I'm led to believe, so that shows how cowardly they are, they're targeting, without being disrespectful, they're targeting the older generation.

"The staff were brilliant, they pulled the shutters down, the police appeared within about five, six, seven minutes, and that was it."

Celtic have now advised fans to follow the extensive guidance issued by the club ahead of the clash.

They said: "We can confirm that two fans have been injured after being stabbed last night.

"Both are now in hospital and will receive every support from the club and the British consulate in Rome.

"Again we would strongly advise supporters to closely follow all guidance issued by the club."

Evening Times: Lazio fans make fascist salutes in GlasgowLazio fans make fascist salutes in Glasgow

READ MORE: Two Celtic fans stabbed in Rome outside Irish pub 'by Lazio ultras'

Tensions had been high ahead of the match, following shocking scenes in Glasgow last week when a group of Lazio fans marched down Buchanan Street making fascist salutes.

Celtic fans responded by holding up a large banner of executed Italian dictator Mussolini with the caption 'follow your leader'.

On Tuesday Hoops chiefs issued a fresh warning to fans travelling to what was being described as a high-risk match.

Italian police put a 37-hour ban on the sale of alcohol surrounding the game and Celtic fans were advised to "stay in large groups",  "keep a low profile" particularly in the evening and "avoid wearing club colours". 

It's thought around 9000 Hoops fans will travel to the Italian city for the match.

Fans have also been advised that anyone using the supporters' shuttle service will be searched by police, with the notice warning "under no circumstances should supporters make their own way to the stadium". 

Once at the stadium, fans will be searched and asked to produce photo ID.

Bags will not be permitted in the stadium and all banners will be checked - with banners containing any political messages not allowed inside.

Celtic fans will be kept in the stadium for up to an hour after the full-time whistle before embarking on a shuttle service back to the city centre.