A sixteenth birthday party at a school hall was crashed by a group of youths with knives who stabbed two teenagers.
Three arrests have been made following the incident at Elm Park Primary School in Havering, Essex, yesterday evening.
Reports suggest as many as 50 young people were in the group that stormed the hall at around 9pm and kicked off fighting until 11pm.
A 19-year-old and a boy aged 16 were taken to hospital with non-life threatening injuries.
The Metropolitan Police said its officers were also among those attacked, but they did not need hospital treatment after being seen by ambulance crews.

Three teenagers who were arrested were taken to a police station in east London and were bailed to later return for questioning.
The mother of a 15-year-old girl who was taken to hospital told Havering Daily: ‘She had gone to a party that was supposed to have correct security but it didn’t and it all went wrong.
‘As she ran scared from the event, she told me the fire exit wasn’t accessible and that as she got on the train, other youths followed and more fighting began.
‘My daughter was attacked on the train and more fights took place. It was awful.’
A Met Police spokesperson said: ‘Police were called shortly after 9pm on Saturday March 22 to reports of a fight involving a group on Calbourne Avenue.
‘Officers attended before engaging with a number of teenagers who became aggressive toward them.
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‘Three teenagers were arrested at the scene on suspicion of assault on emergency workers. They were taken to an East London police station. They were bailed to return for questioning later today.
‘The officers were treated at the scene by London Ambulance Service medics and do not require hospital treatment.
‘Separately, two individuals, including a 16-year old male and a 19-year old male sustained suspected knife injuries and were taken to hospital where their injuries were deemed neither life-changing nor life-threatening. They continue to assist police with their enquiries.
‘An investigating into the circumstances of the incident is ongoing.’
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