Russians have watched with horror this week as the details of the latest US school shooting, in Parkland, Florida, have emerged.
President Vladimir Putin is among the world leaders who have offered condolences to the families who have lost their children.
But there is also real concern in Russia that a problem previously seen as almost exclusively American is now spreading to its territory.
In recent months, Russia itself has experienced a series of school attacks -- including one last September, in Ivanteevka, outside Moscow, and three in the space of a week last month.
According to state media, the teenaged perpetrators used air guns and knives, not semi-automatic weapons, and the victims suffered injuries, with no deaths reported.
But Russian media reports were filled with speculation that at least some of the attacks were inspired by online groups focused on notorious school killings in the United States, particularly the 1999 Columbine High School massacre.
In one of the Russian attacks, on January 15, two teenage attackers armed with knives stabbed a dozen children and two teachers at a primary school in the Urals city of Perm.
Four days later, a teenager armed with an ax and a homemade firebomb attacked a school in the village of Sosnovy Bor, outside the city of Ulan-Ude in the Republic of Buryatia, in eastern Siberia. Six students and a teacher were injured, according to state media.
There was also a stabbing that week at a school in Russia's Chelyabinsk region, in which one student was reported injured.
In Ivanteevka, a teenager brought homemade explosives, an ax and air weapons to his school, according to state news agency Tass. He attacked a teacher with the weapons and set off the explosives. Three students were injured when they jumped out a window to escape.
In the wake of the attacks last month, Russia's Ministry of Communications and Mass Media, or Roskomnadzor, clamped down on social-media groups believed to be manipulating young people's actions.
A statement from the ministry said Russia's Vkontakte social network had deleted nine so-called Columbine communities, and that "posts of a similar nature" had also been removed from four other communities.
It was believed these groups "had illegal information capable of pushing minors to antisocial behavior, the result of which could be acts of a suicidal nature," the ministry said.
Russian state media is often criticized for exaggerating, even gloating at, problems or discord in the West, as a way of deflecting from Russia's own troubles. But the latest horrifying images emerging from the Florida school shooting speak for themselves.
Putin, in a telegram to his US counterpart Donald Trump, sent his "sincere sympathy and support to the families and friends of the deceased, as well as the wishes for a speedy recovery to all the victims," the Kremlin said.
Tanya and Vyacheslav, a couple from Norilsk in central Russia who were visiting Moscow with their children, told CNN they were shocked and saddened by reports on the Florida shooting.
"It doesn't characterize the country but there are some teenagers who do this more often," said Tanya. "We have also had some instances in our country but in America it happens more often. I don't know why. Maybe the children sit and play more computer games."
She said Putin would strengthen security in schools if a similar situation arose in Russia.
Vyacheslav urged increased gun control measures for the United States. "They need to ban guns. Give out licenses under observation. There need to be checks and in a school a search of people. The most important thing is control," he said.
He said Russia had already taken steps to safeguard students. "These measures have already been taken in all schools, there is search and control, we don't have the free sale of weapons in shops -- it's all under license. There are medical and psychological checks."