It’s known as the “Blue Whale Challenge” — a social media game linked to “a recent surge in adolescent suicides in Russia,” said Nassau County Executive Edward Mangano on Thursday, urging parents to monitor their children’s internet activity.

The game is “played through private group messages” on social media sites, led by an administrator who asks teens to “complete 50 tasks over a period of 50 days” and culminating with the participants committing suicide, Mangano said in a statement.

And while authorities said no deaths from the game have been linked to the United States, Mangano encouraged parents to keep tabs on their children to “ensure they remain safe.”

“This is a deadly game affecting teenagers and their families overseas,” Mangano said. “With technology and social media sites so prevalent in our lives, it has become easier for these types of cyber threats to occur.”

Authorities in France, Britain, New Zealand, China and other countries have warned teenagers against participating in the online game, according to international media accounts.

The online site Cafe Mom said in a recent report: “Warnings have been popping up on American school websites and community Facebook pages for weeks now, telling parents to be wary of any reference to ‘blue whale’ in speech or on social media.”

Mangano and police said that tasks required as part of the game include watching horror movies and participating in “self-harming.”

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After 50 days, Mangano said, teens are told to “delete all associated messages and posts” from their social media accounts before committing suicide.

Nassau police said the Russian Federal Security Bureau reported that a 21-year-old Russian man has been arrested for serving as “an administrator of the Blue Whale group,” responsible for encouraging 17 girls, ranging in age from 12 to 16, to kill themselves.

Authorities have said 130 suicides in Russia have been “potentially” linked to the online social media game.

According to Snopes.com, a website that researches the veracity of urban legends and internet rumors, Blue Whale groups apparently exist but none have been linked to the Russian suicides. The link between the game and suicides is therefore listed on the website as “unproven.”