A Polish man was rushed to hospital with serious head injuries after being attacked by a group of up to 20 young men, in what police have described as a racially-motivated attack.
The 28-year-old man was found unconscious by police at around 9.35pm on Friday after being kicked and punched by the gang.
Officers were called to the scene in Alliance Street in Armley, Leeds, after someone reported seeing a large group of young men aged 18 to 20 surrounding a Polish man who was bleeding on the floor.
The victim and his friend were in nearby Town Street when they were confronted by the young men, before the victim ran away and was chased into Alliance Street by his attackers.
The man suffered a cut to his head and is receiving treatment in hospital.
Chief Superintendent Paul Money, Leeds District Commander, said: "I want to reassure people, particularly the local Polish community, that we will not tolerate hate incidents of this nature and will do everything we can to ensure the people responsible are brought to justice.
"Detectives from Leeds District CID are carrying out extensive enquiries into this incident and are checking CCTV in the area and speaking to witnesses."
Alison Lowe, who represents Armley on Leeds City Council, said: "Armley is a tolerant and welcoming community where I lived with my own children for 15 years, without incident.
"This is not the Armley I know and love and I hope our communities will come together to show others that Armley is a safe place to live and work, despite the despicable actions of an ignorant few".
The incident happened the same day that Theresa May spoke to the Polish Prime Minister Beata Szydlo and expressed "deep regret" over racist attacks on Polish citizens.
She reportedly told her counterpart, "hate crime has no place in UK society", following several high-profile racist attacks, including one incident where a Polish family's shed was set alight in an apparent racist arson attack.