A Polish man was chased by a group of 20 men and beaten with a nailed plank of wood in a "racially aggravated assault" in Hull, police said.
The 20-year-old man is being treated for facial and head injuries in hospital.
Three friends of the victim, also from eastern Europe, said they were confronted by the gang while walking to a bus stop at around 7.30pm on Sunday.
They told Hull Daily Mail how they were pursued by the gang before their friend was caught and beaten.
One man, who did not wish to be named, told the newspaper: "When they heard us speaking in Polish they began to shout at us and throw a few bottles."
He said they did "the only thing we could and ran" before his friend was captured and struck by a plank of wood with nails in.
The man added: "He was on the floor for 25 minutes before the ambulance came, and he was in hospital overnight."
Humberside Police confirmed that a group of 20 men had made threats and shouted at the victim before following him to a house on Laxthorpe, near the Orchard Park housing estate.
In a statement it added: "The victim reported that he was struck by a nailed plank of wood and kicked repeatedly in the attack.
"He was taken to hospital and treated for injuries to his head and face.
"We are treating this as a racially aggravated assault and would appeal for anyone that can help us identify those involved to call us on 101 quoting log 520 of 15/04/18."
The friend of the victim said it was not the first time the four had been subjected to what he said was racial abuse, saying that he was "scared to leave him home".
He told the newspaper "this sort of thing happens nearly every day to Polish people here".