MOSCOW (AP) — None of the main Russian television channels carried reports about the arrest of a nanny accused of killing a 4-year-old girl and then waving the child's severed head outside a Moscow subway station, even though videos posted online had caused a sensation among Russians throughout the day.

Russian President Vladimir Putin's spokesman on Tuesday denied that the news was withheld at the request of the Kremlin or out of concerns that the killing could stoke ethnic tensions in a country with many Muslim citizens and migrant workers.

The suspect is a 38-year-old woman from Uzbekistan. Her religion was not known, but she wore a head covering and some witnesses said she shouted "Allahu akbar" while waving the bloody head on the street on Monday morning. In videos posted on Russian news websites, she was heard shouting "I am a terrorist" in Russian.

Investigators said the woman, who was the child's nanny, appeared to be mentally unstable.

Putin spokesman Dmitry Peskov said the television stations made the decision themselves not to air the videos, which he described as "too horrific to show on television."

Most of the TV channels carried reports on their websites and major Russian newspapers also reported the details of the killing, but television is the primary source of news for the majority of Russians across the country.

In memory of the little girl who was killed, Muscovites placed flowers and children's toys outside the subway station Tuesday.

Russian children's rights ombudsman Pavel Astakhov responded to the killing by urging parents to ask prospective nannies to provide a doctor's certificate confirming their mental health.