A 54-year-old man and a 15-year-old boy have been arrested on suspicion of arson with intent to endanger life after a restaurant fire in east London on Friday.
Three people were taken to hospital in a life-threatening condition after the fire at the Indian Aroma in Ilford.
Two remained in a critical condition on Sunday morning, according to the Metropolitan Police.
The restaurant suffered extensive damage in the blaze.
Two further victims are thought to have left the scene before officers arrived, Scotland Yard said.
Police are still trying to identify them.
CCTV footage seen by the PA news agency appears to show a group of people wearing face coverings walk into the restaurant and pour liquid on the floor.
Seconds later, the inside of the restaurant is engulfed in flames.
"While we have made two arrests, our investigation continues at pace so we can piece together what happened on Friday evening," said the Met Police's DCI Mark Rogers.
"I know the community [is] concerned and shocked by this incident.
"I would urge anyone with any information or concerns to come forward and speak to police."
Hospital porter Edward Thawe went to help after hearing screams from his nearby home.
He described the scene as "horrible" and "more than scary and the sort of thing that you don't want to look at twice."
He said: "I heard screaming and people saying they had called the police."
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The 43-year-old said he saw a woman and a severely burned man who may have been customers.
Another witness, who did not want to be named, said he saw three "severely burned" people being doused by the emergency services and given oxygen.
"I can only imagine the pain they were going through," he said.
On Saturday, the London Ambulance Service told Sky News: "We sent resources to the scene, including ambulance crews, an advanced paramedic, an incident response officer and paramedics from our hazardous area response team.
"We treated five people for burns and smoke inhalation. We took two patients to a major trauma centre and three others to local hospitals."
The police investigation is continuing.
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