Juventus superstar Paul Pogba has released a statement as extraordinary reports emerged about an alleged blackmail and kidnap plot orchestrated by his own brother.

French police have confirmed an investigation has been opened into the World Cup winner's claims he is being threatened and targeted for extortion by gangsters.

He is reported to have alleged that the group extorting him includes his own brother and childhood friends.

Pogba's allegations came after his brother Mathias published a bizarre video online — in four languages (French, Italian, English and Spanish) — promising "great revelations" about the Juventus star.

A statement signed by his lawyers, his mother Yeo Moriba and current agent Rafaela Pimenta said that the videos published on Sunday morning (AEST) "are unfortunately no surprise.

"They are in addition to threats and extortion attempts by an organised gang against Paul Pogba," read the statement.

"The competent bodies in Italy and France were informed a month ago and there will be no further comments in relation to the ongoing investigation."

Mathias Pogba, 32, promised "great revelations about (his) brother Paul Pogba and his agent Rafaela Pimenta", who took over as head of the company of former agent Mino Raiola who died in April.

Mathias, himself a professional footballer who has played for 12 clubs, said the "whole world, as well as my brother's fans, and even more so the French team and Juventus, my brother's teammates and his sponsors deserve to know certain things".

Mathias Pogba said people needed to know what he knew in order to judge whether his brother "deserves his place in the French team and the honour of playing in the World Cup. If he deserves to be a starter at Juventus."

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"All this is likely to be explosive," he concluded without adding any substance to his "revelations".

Paul Pogba's brother posted the video to TikTok. Photo / Supplied

According to French newspaper L'Equipe, the brothers were still considered close friends up until recently and they attended a charity event together in Paris in March.

According to two sources close to the Pogba family contacted by AFP, large sums of money are being demanded from Paul Pogba if he wants to avoid the dissemination of the allegedly compromising videos.

France Info reported that Paul Pogba told investigators he had been threatened by "childhood friends and two hooded men armed with assault rifles".

His statement also alleged he was dragged by the gang into an apartment in Paris in March and was then threatened.

The group confronted him again in July where he was reportedly accosted outside of Juventus' training ground. He is reported to have told the team about the extortion attempt following the confrontation and the matter was then handed to police.

The group is reported to have said the demand for money was on the back of a claim they had given him protection over the past 13 years.

The group are demanding 13 million euros ($19m) from him for "services provided". A source close to the matter confirmed the France Info reports to AFP.

Fellow French superstar Kylian Mbappe's name also came up in the affair. Pogba explained to investigators that his blackmailers wanted to discredit him by claiming he asked a witch doctor (holy man) to cast a spell on the Paris Saint-Germain star, which Pogba denies.

Piers Morgan reacted to the news by saying it was "insane".

The group of kidnappers is reported to have followed him during his career in Turin, Paris and Manchester.

Pogba, who won the World Cup with France in 2018, returned to Juventus on a free transfer this summer after six years at Manchester United, and is currently sidelined with a knee injury.

The 29-year-old is expected to return to action next month.

The investigation is reportedly being pursued by France's Central Office for the Fight against Organised Crime.