London - British police said on Friday that two boys aged 15 and 16 are in custody on suspicion of involvement in five acid attacks carried out by two suspects on mopeds the previous evening within the space of 72 minutes.
Both teens were arrested on suspicion of grievous bodily harm and robbery after the crime spree, which started at 10:25 pm (2125 GMT) in the east London borough of Hackney, where two males riding a moped attacked a man with acid and made off with his moped.
The subsequent attacks - carried out by two men on mopeds - occurred at 10:49 pm in the central Islington area, and at 11:05 pm, 11:18 pm and 11:37 pm back in east London, police said in a statement.
All five victims suffered injuries in the attacks, though none of them were in life-threatening condition. However, police described one of the victims' injuries as "life-changing."
Confirming the arrests, Chief Inspector Ben Clark said: "These are hideous offences and must have been very frightening for all of the victims."
"Of late we have seen more attacks using corrosive substances in London. I would urge businesses and parents to challenge those who they think may be trying to obtain or carry these substances as this could help prevent serious offences," he added.
Police has called for witnesses, as well as those with information or in possession of footage of the incidents, to come forward.
Data obtained from the Metropolitan Police by the BBC through Freedom of Information requests shows there have been more than 1,800 reports of attacks involving corrosive fluids since 2010.
Their use had been recorded in murders, robberies and rapes.
British Prime Minister Theresa May referred to the crime spree as "horrific."
She said through her spokeswoman that it was "already an offence to carry acid or a corrosive substance with intent to cause harm" and that her government was working with the police to see what more could be done.
Speaking to LBC radio in the wake of the attacks, Metropolitan Police chief Cressida Dick said: "Acid attacks are completely barbaric. It's a new trend in this country. The acid can cause horrendous injuries."
Jaf Shah of Acid Survivors Trust International said acid attacks had "effectively doubled" in the past year and that that the possession of corrosive substances should carry the same penalty as knife possession to avoid an "explosion" of such crimes.
But the National Police Chiefs' Council (NPCC) said it is virtually impossible to ban the sale of all corrosive substances because many are household products, such as bleach and drain cleaner, which are available over the counter.