A nine-year-old girl of mixed Russian and Malian parentage has been seriously injured in a stabbing in St Petersburg.
Prosecutors said they were considering "xenophobia" as the motive for the attack, in which nothing was stolen.
The attack in the hallway of a block of flats on Saturday evening is the latest assault in the city on foreigners and members of ethnic minorities.
A teenager was acquitted last week of stabbing a Tajik girl aged nine to death in the city two years ago.
Human rights groups were outraged when he and seven others were found guilty of the lesser charge of hooliganism.
In the latest incident, two attackers apparently followed the girl into the entrance hall of her block of flats and stabbed her in the neck and head.
She is said to be in a satisfactory condition in hospital.
Aliu Tunkara, who heads a civic group for Africans in the city, said last week's acquittal in the case of the Tajik girl could lead to more violence.
"Since nobody was punished for the murder of the girl, people with similar nationalist attitudes could now feel that they have nothing to fear in committing such actions," he said.