Russian President Vladimir Putin has signed a law that proponents say is aimed at banning what they call "online Columbine communities" that allegedly encourage violence by schoolchildren.
The law, signed on December 18 and posted on an official website, says it targets information that encourages children to do things that could pose a threat to the health or lives of other people.
It says it also is aimed at "protecting children from information damaging to their health and development."
There have been several attacks on schools in Russia this year, as well as a gun-and-bomb attack on a college in Russian-controlled Crimea in which authorities say an 18-year-old student killed 20 other people on October 17 before fatally shooting himself
Lawmakers who passed the bill earlier in December said the purpose is to shut down websites encouraging violence by schoolchildren.
According to the law, local executive organs are authorized to define websites as dangerous for children and ban them.
The law also says that owners of banned websites must remove them from the Internet or limit access to them immediately after they are placed on an official registry.
Hours before the newly endorsed law was made public, 17-year-old boy was sentenced to nearly 10 years in prison after being convicted over a knife attack at his former school in the city of Perm that left 12 people hospitalized with stab wounds.
The Motovilikha District Court in Perm, 1,150 kilometers northeast of Moscow, found the defendant guilty of the attempted murder of 30 people and of damaging school property.
The boy, whose name was not disclosed because he is a minor, was sentenced to nine years and eight months in prison.
Authorities said the boy and another teenager, a student at the school, entered the building carrying knives and injured 15 people.
The second suspect was found mentally unfit to face trial and sent to a psychiatric hospital.
On December 6, a Moscow secondary school was evacuated after a 16-year-old student brought a knife into the building and threatened to kill himself, officials said.
On November 12, authorities said a 14-year-old boy in the Volgograd region brought an ax, several knives, and a gas canister to his school, and was hospitalized for a day after he swallowed rat poison.
Nobody else was hurt.