A 38-year-old man was attacked in Malmö, Sweden’s third largest city, for the sole crime of hanging an Israeli flag on his window.
The assailants smashed the man's window first, prompting him to seek the perpetrators, police said.
"After that the man went out onto the street to see what was going on. Then he was attacked and it was on the basis of the flag. That is the information we have at present," police told the Swedish news agency TT.
They added that ten people chased the man from his building, wielding iron pipes. He managed to narrowly escape his attackers and was taken to hospital with serious injuries.
The man was beaten with a metal rod.
Police is treating the attack as a hate crime and "aggravated assault."
In recent years, anti-Semitic attacks have been on the rise in Malmö and many in the city's Jewish community have left, or are considering leaving, Malmö.
Several hundred Jews live in this city of approximately 300,000 people. A third of the population is made up of people who were born in Muslim countries or whose parents were born in those countries.