A group of men sprayed a "noxious substance" at shoppers in London Saturday night, injuring at least six people, police said.
The Metropolitan Police said a 15-year-old boy was arrested on suspicion of causing grievous bodily harm at the Westfield Stratford Shopping Centre in east London, Sky News reported.
"So far we have treated at least five patients at the scene and taken three patients to hospital," said London Ambulance Service assistant director of operations Paul Gibson. "We remain on the scene."
Gibson later confirmed at least six people were treated for injuries, with three people hospitalized, according to Sky News. All the injuries were non-life threatening.
Two groups of men got into an argument when the attack happened, said Chief Superintendent Ade Adelekan, Newham borough commander. A witness said he saw one man screaming while his friends shouted, "It is an acid attack, his skin is burning!"
A man who gave his name as Hossen, an assistant manager at Burger King, said he saw a victim and his friend, a local homeless man, run into the restaurant's bathroom to "wash acid off his face."
"There were cuts around his eyes and he was trying to chuck water into them," the man said.
It's unclear if the incident is terror-related.
The shopping center opened in 2011 and is located near the site of the 2012 Summer Olympics.