A woman has been charged with murder after walking near a Moscow metro station holding a child's severed head

A nanny has been charged with murder after footage showing her walking near a Moscow metro station carrying the severed head of a child was published in Russia.

Russia Today tweeted a picture showing the woman, dressed all in black, on the street near Oktyabrskoye Pole metro station in north west Moscow on Monday morning.

According to Life News she was shouting "I am a terrorist," as she walked with the severed head in her hand.

Moscow investigators told Reuters the woman was a nanny from Central Asia and that she was undergoing psychiatric testing to see if she was mentally sound.

Life News said a policeman had approached the woman to inspect her documents and that she had responded by removing the child's head from a bag and begun yelling that she had killed the child.

One reporter, from RBC, said the woman had also been heard screaming "Allahu Akbar" (God is Great).

Investigators said the murdered child was three or four years old and had been killed in her family's Moscow flat before it was set on fire.

The motive for the crime was unknown, they said.