A Russian police officer stands at the site where a woman suspected of murdering a young child was detained Monday, near the Oktyabrskoye Pole metro station in Moscow. Reuters/Maxim Zmeyev

A nanny carrying the severed head of a 4-year-old boy shouted near the entrance of a subway in Moscow, threatening people as they passed by, before being arrested, Russian media reported Monday. The suspect, who appeared dressed in hijab on CCTV footage, was reportedly placed in psychiatric care to determine whether she was capable of understanding her actions, the BBC reported, citing an official Russian statement.

The suspect was named as Gyulchekra Bobokulova and was born in Uzbekistan, a former Soviet republic in Central Asia, according to Russian media. Amateur video posted online appeared to show the black-clad woman yelling “Allahu Akbar,” which means “God is great” in Arabic.

“I am a terrorist,” she reportedly said. “I am your death.”

Some witnesses said the woman walked around the metro station for around 20 minutes carrying the decapitated head before she was arrested. A journalist who happened to be on the scene, Polina Nikolskaya, said the woman caught her attention as she yelled "Allahu Akbar." Much of her ramblings were reportedly nonsensical.

"I saw that she had a bloodied head in her arms, but I thought it was not real. People in the crowd said it was real," Nikolskaya said.

Footage from the incident reportedly showed police wrestling the woman to the ground. A criminal investigation was launched; she is believed to have set fire to the apartment where the child’s parents lived.

"According to preliminary information, the child's nanny, a citizen of one of the Central Asian states and born in 1977, waited for the parents and elder child to leave the flat and then, for reasons not established, murdered the infant, set fire to the flat and left the scene," the Moscow Investigative Committee said in a statement, the BBC reported.

Russia has faced a protracted Muslim insurgency in the North Caucasus and Moscow has in the past been a target of terrorist attacks. There was no evidence that the incident Monday was tied to terrorism. It is not uncommon for migrant laborers from Uzbekistan, a Central Asian country with a majority Muslim population, to live and work in Moscow.