Two children are said to have taken their own lives after playing a disturbing online game which encourages self-harm and which has been spreading through social media.

The viral game, which started on Facebook, requires children to message a fictional horror character called Momo by contacting an unknown number. They are then set a series of challenges, ending in a demand they take their own lives.

The latest deaths, of a 12-year-old girl and a 16-year-old boy, took place within 48 hours of each other, with both children in the municipality of Barbosa, in Colombia. Local media reported that the pair knew each other, and the boy had passed the game on to the girl.

Government secretary Janier Landono said: "Apparently, they practised this game through WhatsApp and it invited the young people to hurt themselves. The game has different challenges and the suicide is at the end."

WhatsApp is an instant messaging app owned by Facebook.

The "Momo game" has been compared to the "Blue Whale" challenge, which started in Russia in 2016 and which led to numerous reports of suicides, although no deaths were definitively connected with "Blue Whale".