An investigation has started after two boys were found dead at a home in Dagenham, east London, the Metropolitan Police said.
A man and a woman have been arrested in connection to the incident.
The boys, aged two and five, were found at the property in Cornwallis Road by emergency services, and both were confirmed dead at the scene.
Police and London Ambulance Service crews attended after being called at about 14:00 GMT.
Officers said family had been informed about the boys' deaths and were being supported.
The arrested woman and man were known to both children, the police force said.
Officers said the woman was arrested after police were called to a disturbance at a residential address near to the scene.
The man was arrested near to the scene in connection with the incident, the Met said.
Det Insp Sean Treweek said: "This is clearly an extremely distressing incident with many unanswered questions, however at this very early stage, nobody else is sought in connection with the deaths.
"I want to thank local people for the assistance they have given officers as they begin work along with partner agencies to establish the full circumstances of these two tragic deaths.
"They will see additional officers in the area, and anyone with information or concerns should speak with those officers."
Councillor Elizabeth Kangethe, who lives a short distance from Cornwallis Road, said there was a "heavy police presence" on Friday evening.
"They are talking to the locals to reassure us and they have told people who they can contact if they have any concerns, because people will be traumatised," she said.
"It will be upsetting for everyone, not just the local community, anyone hearing this will be affected, everybody will be shocked, especially being so near Christmas."
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Metropolitan Police
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