Teenager arrested after video of alleged racist attack on Barcelona train goes viral

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.