Vladimir Putin has been asked to tell the world what he knows about aliens.

US citizen, Stephen Bassett, executive director of the Paridigm Research Group International (PRG), has spent a week in Russia trying to convince Mr Putin of the importance of lifting an alleged "truth embargo" that stops world leaders telling the public the truth about aliens.

Mr Bassett, who is the only registered lobbyist in the US on the subject of alien disclosure, believes a conspiracy theory that the truth of aliens has been withheld due to the fear of the impact on religion and the rule of law if we all knew.

He believes the conspiracy has been in place since at least 1947 when a flying saucer allegedly crash landed at Roswell, New Mexico.

Mr Bassett was interviewed for a Russian documentary during his visit.

A PRG statement said: "During the interview, which will be broadcast in Russian in August, Bassett discussed various considerations that might prompt Russian President Vladimir Putin to make the first formal acknowledgment by a head of state regarding an extraterrestrial presence engaging the human race.