Two boys have been injured after a suspected corrosive substance was thrown at them during an attack on London Underground.
CCTV images have been released of three people wanted by police following the assault at Elm Park tube station shortly after 8pm on February 24.
The victims went to hospital but their injuries are not thought to be life-threatening or life-changing.
Still images released by the British Transport Police show two men and a woman.
One of the men can be seen wearing a black puffer jacket with a black face covering and black hat, while the other is dressed in a black coat.
The woman in wearing a cream jacket with blue jeans and Converse trainers, and can be seen clutching a green jacket folded over her arm.
It is the latest in a series of recent reported corrosive substance attacks and comes a month after a mum and her two young girls were targeted in Clapham, south London.
Detective Inspector Marvin Bruno said: ‘Violence in any form will not be tolerated on the rail network and we would like to reassure the travelling public that our officers are working tirelessly to identify and apprehend those responsible.
‘We are really keen to speak to the people in the images, or anyone else who witnessed the incident, as we believe they have information which could help our investigation.
‘If you know them or have any information that might help, please get in touch.’
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There have been four similar attacks in the south of England in the past month alone.
The most high profile of these was that carried out by Abdul Ezedi, who doused his former girlfriend and her children, aged eight and three, in a corrosive substance during a harrowing attack in Clapham.
His body was pulled from the Thames last week following a nationwide manhunt.
In another attack, a 52-year-old woman suffered burns to her head and back after a corrosive substance was thrown over her at a pub in Basingstoke on February 10.
A day later, a manhunt was launched after a man was hurt in a ‘noxious substance’ attack at a graveyard in Ramsgate, Kent.
Police officers in Croydon, south London, were involved in a three-hour stand-off that same day with an alleged acid attacker who seized a bus and threatened the driver and passengers.
A 44-year-old man was held for affray and it was later confirmed the substance involved was not harmful and nobody was hurt.
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