When Warren Air Force Base in Wyoming lost control of 50 nuclear, inter-continental missiles last October, officials said a communication failure between the control centre and the weapons was to blame.

However, three missile technicians stationed at the base have raised fresh questions in the case, amid reports UFO sightings coincided with the incident.

UFO researcher Robert Hastings says eyewitnesses claim the interruption to the power supply also lasted much longer than the Air Force admits.

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Cover-up claims: Missile technicians stationed at Warren Air Force Base in Wyoming have reported UFO sightings coinciding with October's power outage

A power failure on October 23, 2010 meant that one-ninth of America's nuclear arsenal went offline for almost an hour.

A U.S. Air Force spokesman said there had been a 'hardware issue' relating to an underground cable linking the command centre with the missiles.

This disrupted 'communication between the control centre and the missiles, but during that time they were still able to monitor the security of the affected missiles'.

Defence officials insisted there was never any danger of an accidental launch. But the incident was deemed serious enough for Barack Obama to be briefed on it later.

Speaking out: UFO researcher Robert Hastings says three eyewitnesses have come forward to him on the condition of anonymity
There was no evidence of foul play and the U.S. never lost the capability to launch the missiles, although it could only have done so from an airborne command and control centre, he said.

Another official said there had been similar breakdowns on other bases in the past.

But Robert Hastings says more was involved.

According to Hastings, three missile maintenance technicians have agreed to speak to him on the condition of anonymity, revealing the military has kept UFO sightings that occurred during the power outage under wraps.

The witnesses, he said, reported sightings of 'a large cigar-shaped object high above the missile field'.

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Hastings told AOL: 'They said the object was seen in the sky above the field, throughout the weekend, both during the (missile) disruption and the following day.'

His witnesses claim the power outage lasted several hours longer than officials reported.

'I have detailed information about the events. The Air Force said this (missile) disruption lasted 59 minutes. It actually lasted the better part of 26 hours,' he said.

'It was intermittent and involved a very specific sequence of these five missile alert facilities going on and offline. I have all of that down to the most minute detail.'

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Blast: A Minuteman nuclear-tipped missile takes off from its launch facility at Cape Canaveral Air Force Station, Florida
The eyewitnesses agreed that what they saw 'was not a commercial blimp.'

'It had no passenger gondola and no advertising on its hull,' Hastings said.

'Further, its aspect ratio (length to width) was very similar to a WWI Zeppelin: long and thin, and not at all like the squat shape of a corporate blimp.'

The witnesses did not, however, claim the alleged UFO was connected with the outage.

It is not the first time Hastings has reported UFO sightings at nuclear missile sites.

He organised a press conference last September, when six former Air Force officers stepped forward to reveal they had seen or had been involved with sightings at missile sites.

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Going public: Captain Robert Salas accused the U.S. Air Force of lying in September
They claim that since 1948, aliens have been hovering over UK and U.S. nuclear missile sites and deactivating the weapons - once even landing in a British base.

The men said they were encouraged not to speak to the media about their sightings.

Captain Robert Salas, who was among the six, confirmed: 'We're talking about unidentified flying objects, as simple as that.'

However, Lieutenant Colonel John Thomas, director of public affairs for Air Force Global Strike Command headquarters at Barksdale Air Force Base in Louisiana, denies there is a policy to silence eyewitnesses to unexplained phenomena at Air Force bases.

'I have no reason to dispute anybody's claims of anything they may seen historically, because those occurrences and reports took place decades into the past and probably will decades into the future,' he told AOL.

'This incident is separate from all of that. We took it very seriously and we're very confident that we understand fully what happened.'

'If people see things that are unusual, they are encouraged to report them,' he said, adding: 'When people join the military, they don't give up their First Amendment rights.'