A gang of Arabs brutally attacked an American yeshiva student visiting with his family in Venice, Italy, in what local community leaders said was a rare instance of anti-Semitism.

The student was knocked unconscious on Tuesday when he strolled late at night in the center of the city. A band of 15 Arab youth pounced on him, dragged him into a dark corner and pummeled him, using sharp weapons.

The student lost consciousness, and the attackers fled when a passerby spotted them and called police and medics.

The police are investigating, but have but have not caught the attackers.

The Milan-based Center for Jewish Documentation’s Observatory on Anti-Jewish Prejudice reported last month that the number of anti-Semitic episodes in the country soared last year.

The incidents ranged from street insults and swastika graffiti to physical aggression.

”We observed approximately 70 cases so far this year, most of them graffiti and online attacks, over 40% more than last year,” said Observatory researcher Stefano Gatti. ”The boom might be due partly to more efficient data-gathering, but the episodes have undeniably increased,” he added.

Gatti also pointed out that Italian pundits and politicians ”such as Silvio Berlusconi, Beppe Grillo or Piergiorgio Odifreddi” are now writing discriminatory posts and telling racist jokes. ”Making certain issues seem normal, even funny, is one of the root causes of the rise in anti-Semitic episodes in Italy,” Gatti said.