SAINT PETERSBURG, April  3, 2017 (AFP) - Chilling online "death groups" on popular social media that egg on teenagers to kill themselves are causing panic in Russia after a string of teen suicides.

Hidden groups on social networking site VK, the Russian equivalent of Facebook, are reportedly controlled by "mentors" who incite their members to take their own lives.

The existence of these groups, highlighted in an investigation by Novaya Gazeta opposition newspaper last year, has rattled parents and sparked heated debate in a country where suicide is largely a taboo subject.

President Vladimir Putin has publicly expressed concern, this month calling for harsher punishments for those convicted of incitement to suicide -- a crime that currently carries a prison sentence of up to three years.

Several dozen Russian teenagers out of the total of 130 who committed suicide between November 2015 and April 2016 were pressured by members of "death groups" on VK, who remain in the shadows as they spread a suicide cult, Novaya Gazeta reported.

A "mentor" on one death group, 22-year-old Filipp Budeikin, was arrested by investigators in the city of Saint Petersburg in November after allegedly inciting 15 teenagers on VK to commit suicide.

In an interview with local media shortly before his arrest, Budeikin outlined his tactics to attract teens he referred to as "biodegradable waste" and "people who are worthless for society."

"First you have to create groups with depressing content that plunges you into a special atmosphere," he said. "People click on links and enter a closed group. That's when the game starts."

Budeikin admitted he asked his victims to share personal information and perform certain "tasks", which often involved self-mutilation or scarification.

"I just explained to some people why it was best to die, nothing more," he said. "They are the ones who made that decision. No one forced them."

Budeikin added that he was simply "cleansing society".

"Death groups" even threaten to blackmail their members by telling them they will go after their loved ones if they refuse to carry out the tasks, Novaya Gazeta reported.

        - 'Urban legend' -

The discovery of the VK death groups sent a jolt through Russian society, where the suicide rate among minors -- 20 for every 100,000 people -- is three times higher than the global average, according to World Health Organization (WHO) data.

Russia's children's ombudswoman Anna Kuznetsova said this month that the suicide rate among minors had increased nearly 57 percent last year after dropping in previous years, attributing the phenomenon to the "death groups."

These groups have also spread to neighbouring Ukraine, where the authorities have sounded the alarm over a significant increase in teen suicide.

Ukrainian police blocked access to 500 social media groups this month, saying they receive on a daily basis "nearly 70 alerts regarding runaway minors, 20 to 30 percent of whom are members of a death group."

Despite the apparent impact the groups have had in Russia and Ukraine, experts think the phenomenon might not be as widespread as it seems.

Some have accused Novaya Gazeta of overblowing its findings and of creating an urban legend out of a few isolated cases of teen suicide.

"This is not the first time panic has struck over an increase in suicide among minors," Meduza news site quoted demographer Yevgeny Andreyev as saying.

"Statistics don't back up" this trend, he added.

Rosstat national statistics agency published data that 22,839 people committed suicide in 2016, down from 24,982 in 2015, without differentiating age groups.

The latest figure has more than halved from 2005 when there were 45,800 suicides.

Suicide, as a subject for discussion, is still shied away from in Russia, adding to the difficulties in tackling it.

It came second only to sexual problems in a November survey by Levada independent polling agency, on topics considered unacceptable to talk about in the family.-AFP