A major search for a "suspect" is under way in a London park after a one-year-old boy died and a girl of the same age was left in a critical condition.

Officers were called to reports of two children injured in a flat in Wilberforce Road, near Finsbury Park, in north London at 11.10pm on Saturday, Scotland Yard said.

Both toddlers, believed to be twins, were found with critical injuries and were taken to an east London hospital where the boy died in the early hours of Sunday morning.

The girl remains in a critical condition. No arrests have been made.

Witnesses heard a woman shouting for help on the street outside and later saw two children being carried out of the property.

Mihai Manea, 29, who lives on the second floor of the building, said the children were twins and lived on the top floor with their Romanian mother and Indian father.

The father worked at the nearby Pembury Hotel as a receptionist, where Mr Manea also works, until a few days ago, he said.

A woman living opposite the building, who gave her name as Gui Gui, said she heard a woman shouting late last night and opened the window to offer help.

"I was watching TV," she said. "I heard someone was shouting.

"She kept on shouting. I do not know what she was shouting.

"I opened the window and I asked her 'Can I help you, can I call the police for you?'

"She said, 'My kids'."

She later saw two young children being carried out of the building, with one being held very close to a member of the emergency services.

Mr Menea described the mood inside the property as "tense".

"It's really tense," he said. "There's police coming and going all the time."

A police car remains parked outside the white three-storey building and neighbours said officers had been searching properties along the tree-lined street.

The Metropolitan Police said: "Next of kin are aware. Formal identification awaits and a post-mortem examination will be scheduled in due course."

They added that inquiries were under way to "establish the full circumstances of the incident".

The National Police Air Service helicopter tweeted that it was assisting "officers searching Finsbury Park for a suspect".