A one-year-old girl and a three-year-old boy have been stabbed to death at a home in Aldborough Road North in Ilford, east London.
Police were called to the home around 17:30 on Sunday but the girl was pronounced dead at the scene, while the boy died in hospital.
A 40-year-old man was also taken to hospital with knife wounds. Police said all three were all known to each other.
The Metropolitan Police has launched a murder investigation and they said they were not looking for anyone else in connection with the deaths.
Jas Athwal, the leader of Redbridge Council, said:
“Earlier today there was an incident in Ilford. Two young children have passed away & an investigation is ongoing.
My thoughts are with the family and wider community who are grieving this unspeakable tragedy.”
There have been 21 fatal stabbings in London so far this year – six of them are known to have happened in the borough of Redbridge.