Spanish police have arrested a teenager suspected of beating up a Mongolian man inside a Barcelona subway train in an alleged racist attack after a video of the incident posted online went viral.
The 56-second video shows a blond youth, dressed in a black T-shirt and jeans and whose face is pixellated, repeatedly punching the seated man before other passengers intervened late on Saturday.
It was reportedly first posted on Sunday to a Twitter account that contained Nazi symbols and the slogan: "Always a patriot, white Europe".
The owner of the account, who appeared in his profile picture with a shaved head and his mouth covered by a bandana, tweeted that he had filmed his friend carrying out the attack on his mobile phone.
The victim, a 25-year-old Mongolian man who lives in Spain, filed a complaint with police on Sunday.
Police said in a statement on Monday they had detained a young man who is suspected of carrying out the beating and charged two others, including another minor, who acted as accomplices.
Police did not give the nationality of the suspect who was arrested, but Spanish media reported that he was Russian.
The video, which was repeatedly played on Spanish television stations and had over half a million views on YouTube, sparked angry reactions from anti-racism campaigners and government officials.
"We want to make it clear that attitudes like this are not acceptable in our city," Barcelona city hall said in a statement.
In 2007 a Spanish man was videotaped repeatedly punching and kicking a 16-year-old Ecuadorean girl.
He was jailed in March for eight months.