A nanny in Russia accused of murdering and then decapitating a little girl in her care has said that "Allah ordered" her to carry out the act.

Gulchekhra Bobokulova, a 38-year-old mother of three, spoke to reporters on her way into a Moscow court.

Bobokulova, a Muslim and a citizen of Uzbekistan, also replied "yes" when asked if she accepted her guilt.

CCTV appeared to show her, dressed in a hijab, walking near a metro station with a head in her hands.

Russian media reported that she pulled the head out of a bag and began screaming that she would blow herself up after a police officer asked to see her identity documents.

Investigators believe she waited for the four-year-old girl's parents to leave the home before killing her, setting the apartment on fire and fleeing, the Moscow Times reported.

Moscow residents have left flowers and children's toys outside the Oktyabrskoye Polye metro station, where Bobokulova was arrested, and outside the murdered child's home.