Russian media reported Monday that a woman working as a nanny in Moscow had decapitated a four-year-old boy and then held his head up while shouting at people near the entrance to a subway station before being arrested.

Amateur videos posted online showed a woman in black, traditional Muslim dress, waving what appeared to be a child's head around while shouting "Allahu Akbar" (God is great) and threatening to blow herself up outside the station in northwest Moscow.

The woman's ranting, recorded by several people who posted videos online, was largely nonsensical but included mentions of terrorism.

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According to the reports, police said she was arrested immediately and that no explosives were found. Local media cited authorities as suspecting it was a case of mental illness rather than a terrorist incident. There were reports suggesting she might have been under the influence of drugs during the incident.

The reports indicated that the suspect killed the child in a nearby apartment, then set the home on fire before walking out into the street.

Some media outlets said investigators had identified the woman as a 38-year-old national of Uzbekistan.