Six people were taken to hospital after a group of males reportedly sprayed a noxious substance near a busy shopping centre in east London, London Metropolitan Police said.
“A number of attacks” were reported around the Stratford Centre, with one male arrested on suspicion of causing grievous bodily harm.
The victims’ injuries are said to be non-life-threatening.
READ MORE: People once used knives, now acid is a weapon of choice in the U.K.
Photographs posted online showed police officers crouching over an apparent victim of the attack as they treated him.
Acid attacks have long been a problem in parts of South Asia, but have become increasingly commonplace in London in recent years.
Over 450 such attacks were reported in the British capital in 2016, compared to 261 in 2015 and around 150 in 2012, according to London Metropolitan Police statistics.
Police said Saturday’s incident is not being treated as terrorism-related.