A woman has been charged with murder of a young child after she was arrested outside a metro station in Moscow.
Footage has circulated online of the woman, wearing a hijab, in the street holding the child’s remains.
"I am a terrorist, I want your death," she can be heard screaming in heavily accented Russian in a rambling tirade in which she appears to criticise democracy and talk about the end of the world.
Investigators said they thought the woman had been working as a nanny for a Moscow family and had murdered a child in her care before setting fire to the family's flat and fleeing.
The child was three or four years old, they said.
News agencies cited an unnamed police source as saying the woman appeared to have been under the influence of psychotropic drugs.
Immigration authorities told media the woman was from the former Soviet republic of Uzbekistan and had been working in Moscow illegally.
One eyewitness, a reporter from the RBC.ru news portal, said she heard the woman screaming "Allahu Akbar" (God is Great).
Lifenews.ru, an online news portal with close contacts to the police, said a policeman had first approached the woman to check her documents near the Oktyabrskoye Pole metro station in the north-west of the Russian capital.
The woman had responded by removing the child's remains from a bag and shouting that she had killed the infant, it said, saying she had also threatened to blow herself up.
Footage of the incident showed a policeman wrestling the woman to the ground before a group of colleagues helped restrain her.
Security services are on high alert for a possible terrorist attack after a Russian passenger plane was blown out of the sky above Egypt in October, killing all 224 people onboard.
The so-called Islamic State said it was responsible and had acted to avenge the Kremlin's decision to launch air strikes in Syria.
