Three people have been stabbed in east London after reports of a large fight, police have said.
Emergency crews were called to River Road in Barking at around 11.20pm on Saturday.
They found three men - aged 22, 23 and 28 - with stab wounds. All three were taken to hospital, and the 22-year-old remains there in a critical condition.
The other two were later discharged and taken into custody after being arrested on suspicion of attempted murder.
The 23-year-old became unwell in custody and was returned to hospital, the Metropolitan Police said.
Chief Inspector Mo Mahmood said: "Our thoughts are with the critically injured man and his family at this very difficult time.
"We understand the concern this incident will have caused for the local community and officers continue to work at pace to understand what happened."
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He said it was an "isolated incident" and that police patrols would remain in the area over the coming days.
"We know there were a number of people in and around the area at the time of the incident and are appealing for any witnesses or those with information or mobile phone or dash cam footage to please come forward," he said.
"No detail is too small."
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