The September 11, 2001 incident in the United States is one of the biggest lies that have been told to the American people, a former CIA contractor says.

Steven D Kelley made the remarks in an interview with Press TV on Thursday while commenting on a report which says the Central Intelligence Agency (CIA) had issued legal threats against the producers of the documentary film “9/11 Press for Truth” who found explosive evidence of a cover-up regarding the intelligence the agency had.

The CIA contacted producers Ray Nowosielski and John Duffy on September 8 regarding their extensive research, interviews and findings that led them to discover the identities of two key CIA analysts who were instrumental in covering-up the 9/11 attacks.

“Normally, with a story such as this, they try not to give any energy to it, because that’s only going to give publicity and give more credibility to the story,” Kelley said.

“In this particular situation where the producers of the film are actually dealing directly with the CIA, and presenting information... that they were asking permission to interview these people under the pretence of assuming to do everything proper, I suspect that the agency had no choice but to take advantage of restricting who they were able to talk to,” he added.

“I would think that it would have been more effective that if they just really seek information in spite of them. I think the threats that this is going to be a federal offense, it could be a hollow threat,” he stated.

“If you look at the whole issue of 9/11, this is one of the biggest lies of course,” the analyst noted.

The September, 11, 2001 attacks, also known as the 9/11 attacks, were a series of strikes in the US which killed nearly 3,000 people and caused about $10 billion worth of property and infrastructure damage.

US officials assert that the attacks were carried out by al-Qaeda terrorists but many experts have raised questions about the official account.

They believe that rogue elements within the US government orchestrated or at least encouraged the 9/11 attacks in order to accelerate the US war machine and advance the Zionist agenda.

A special review commission on 9/11 has found that disagreements still persist within the FBI over whether there was a broader conspiracy in the US to carry out the 2001 attacks.

Aspects of the continuing inquiry, which is the largest in FBI history, suggests that others inside the US had advance knowledge of the operation and supported the suicide hijackers.

“And with the failure of the Americans to sell the ISIS [Daesh/ISIL] lie, and with Putin’s continual questioning of things that the Americans and NATO would have you think they've been doing, the world is certainly waking up,” Kelley said.

“There is going to be enough people eventually that see through these lies,” he pointed out.

“And if they do reach that point, they are going to naturally question the lies they were told surrounding the entire incident of 9/11. And that is a sort of thing that could really bring an end to what we see as, the American government today,” he observed.