Several hundred people, including neo-Nazis, assaulted immigrants in the Athens neighborhood of Patission, after a murder blamed on foreigners.
Shouting "foreigners get out," the mob earlier attacked immigrants in the street and vandalized at least one foreign-owned shop, police said.
Police used tear gas to keep protesters away from a squatter home in Patission.
The violence broke out after a 44-year-old man was stabbed to death early Tuesday as he prepared to take his pregnant wife to hospital.
UPDATE: Fixed headline