Praxilla Trabattoni / NBC News

California native Nicholas Burnett, 20, stabbed in a pub in Rome where he was on his semester abroad studying at Temple University.

ROME — An American college student suffered a foot-long stab wound and a punctured lung when a mob of up to 50 masked men armed with knives and baseball bats suddenly charged English soccer fans and others in a piazza in Italian capital Rome, he told NBC News.

Local media initially blamed Thursday's attack on hard core fans or "Ultras" supporting soccer team Lazio — who played English team Tottenham on Thursday — but two fans of bitter rivals Roma were among a group of 15 detained for alleged involvement in attack, suggesting a different motive.

Witnesses told local media that the attackers shouted "Jews, Jews" as they laid siege to the bar in a district popular with tourists in an old quarter of Rome, raising fears of far-right, racist violence, Reuters reported.

Ten people were injured in the attack and 25-year old Ashley Mills, reportedly an English Tottenham supporter, was left in critical condition. Mills was still hospitalized on Friday, the wire service said.

Tried to run
Nicholas Burnett, 20, of Anaheim, Calif., told NBC News he was standing outside the bar with some friends when he saw "40 to 50 storm into the piazza."

At first, he said they looked "just like a bunch of guys wearing costumes," but the seriousness of the situation quickly became clear.

"Some were wearing helmets, others had scarves covering their faces and all of them were carrying weapons, of all sorts. Sticks, bats, wooden planks, some were swinging their thick belts with heavy buckles," Burnett said.

"All of a sudden they started charging towards the bar. I tried to run away from them and one of the guys broke away from the crowd and took a swing at me over the head with what I though was a baseball bat," he said.

"But judging by my wound it was not a baseball bat, but more like a knife. I ran as fast as I could away from them. ... A couple of minutes later, I realized I was bleeding when I touched my back and felt the T-shirt all wet," he added.

Yara Nardi / Reuters

A pub is seen damaged after a fight in downtown Rome on Thursday.

As he fled, he met two students from John Cabot University, who tried to hail a taxi to take him to hospital, but the first driver "refused to take me in his car because I was all bloodied and still bleeding profusely," Burnett said.

Read more World stories from NBC News

Burnett, who is on a semester abroad at Temple University in Rome, where he is studying business and Italian, was stabbed in the upper-right side of his back down to his left side, he told NBC. The stabbing punctured his right lung, he said.

"I had so many stitches that when I asked the doctors how many they were, they weren't even able to tell me. They simply said, 'Too many,'" he said.

'Very, very scared'
Burnett said he was initially unable to speak to the police because of the pain, but said he had been getting "great care" from medical staff.

"I would like to tell my friends and family back at home that I am OK," he said. "Although I was very, very scared."

Burnett said the attackers moved in unison like "clockwork."

"I don't know how they organized it so well, but that's what made it so scary ... to see them all coming at once threateningly waving what appeared to be makeshift weapons," he said.

Complete Europe coverage on NBCNews.com

He said the attackers were "hurling anything they could find ... including chairs, tables, stools, bottles, shards from the broken windowpanes, bottles, glasses," he said.

Rome Mayor Gianni Alemanno has expressed deep concern about the attack and said he hoped the police would quickly track down those responsible.

"We were all just having a drink, we weren't there for the football (soccer). I don't care for football at all and I don’t know anything about it," Burnett said.

NBC News' Ian Johnston and Reuters contributed to this report.

More world stories from NBC News:

• Amid the ruins, Gazans say pity the living, not the dead
• 'Nail house' holds up traffic as homeowners fight local government
• China's latest supermodel? A 72-year-old farmer
• Despite US woes, Twinkies reign supreme on the Nile
• Analysis: Why Hezbollah sat out the Gaza conflict

Follow World News from NBCNews.com on Twitter and Facebook

LONDON -- A young man was stabbed to death on one of London's busiest shopping streets as thousands took part in post-Christmas sales on Monday.

The victim, 18, died near the Foot Locker sports shop at the junction of Oxford Street and Stratford Place at about 1.45 p.m. GMT (8.45 a.m. ET) close to Bond Street Tube station, reported BBC News.

Pictures on Twitter showed medics trying to save the man, who the newspaper said staggered from the store before collapsing on the pavement.

A Metropolitan Police spokesman said 10 people had been arrested but was unable to confirm if the victim had been involved in a dispute over a pair of shoes.

"It is too early to tell for certain," he said. "As you can imagine, there are literally dozens of witnesses in what would have been an extremely crowded street and it is going to take time to sort out what exactly happened."

A section of Oxford Street from Bond Street Tube station towards Selfridges department store was closed while investigations continued.

Several shops in the area have been forced to shut early because they were inside the police cordon.

An employee at the nearby Disney Store told BBC News the company's outlet was "unlikely to open again today."

msnbc.com's Alastair Jamieson contributed to this report.