Gatineau, Que., police are warning the public about a new viral phenomenon called the "Momo Challenge," in which people are sent disturbing images on social media and asked to complete dangerous tasks.

People who receive a photo of a woman's sculpture on the messaging app WhatsApp are invited to contact an account and do as they're told.

If they refuse, they are told the woman will visit them at night or will launch a curse.

The Momo Challenge is believed to be a hoax. It's unclear how many videos exist or to what extent they have circulated, among children or elsewhere. (Twitter )

The international phenomenon has been linked in media reports to the suicide of a 12-year-old girl in Argentina.

In Gatineau, at least one person was approached to face the challenge, police said.

Gatineau police service spokesperson Isabelle Vachon said people should not engage in this challenge, adding that people who do decide to participate may be exposed to harmful, risky activities.

"If they commit offences because of this challenge, they can be arrested and possibly face criminal charges," she said.

Police are asking residents to avoid contacting a Momo account.

Block number immediately, expert says

Cybersecurity expert Antoine Normand said in French-language interview with Radio-Canada that this phenomenon could grow.

"It is certain that there is not just one Momo account," said Normand, who is the president of Gatineau-based cybersecurity organization​ In-Sec-M.

"[This] has become viral. The more it becomes viral, the more people [there will be] who create accounts and who claim to be Momo."

If a person is currently in communication with a Momo account, Normand advises them to block the number immediately and to do a complete reset of the device.

Gatineau police, Ottawa police and the RCMP say they are carefully monitoring the phenomenon and its spread.