A Briton was among four people stabbed in football-related clashes in central Rome, according to Italian media reports.

Fighting broke out shortly after 9pm on Wednesday at a bar in the Monti area before continuing outside. About 40 people were involved in the clashes, which took place before a Europa League match between Lazio and Sevilla at the Olympic Stadium on Thursday night.

Two Spanish people and an American were also stabbed, with the Briton and one of the Spaniards in a serious condition at Santo Spirito hospital, Gazzetto dello Sport reported.

It is unclear whether the Briton was among the football fans or a tourist who was caught up in the brawl. Police are trying to establish whether Italian football fans known as “ultras” had infiltrated the group.

Witnesses told the newspaper La Repubblica they saw “dozens of people running around, dressed in black”.

“Others wore helmets and had sticks and belts in their hands. It was as if they were chasing someone,” one said.

The fighting began on Via Leonina, which is frequented by tourists and shows live football matches. Some of the fans sought refuge in nearby bars and restaurants.

A bar owner told La Repubblica: “It was quiet and then shortly after 9pm we suddenly heard shouting and the sound of broken glass.

“One of the Spaniards, who had a leg injury, came into our bar. He asked for help, he was scared and upset.”

Italy’s ultras tend to be well organised and can be extremely violent.

Last year, Daniele De Santis was jailed for 16 years for the murder of a Napoli fan, Ciro Esposito, before the 2014 Italian Cup final against Fiorentina.

In November 2012, two Tottenham Hotspur fans were attacked by football hooligans while having a drink at a bar in Rome before a Europa League match against Lazio. Two men were jailed for the attack in 2013.