The US Navy has confirmed that three videos claiming to be leaked military UFO footage are genuine.

The clips taken in 2004 and 2015 show several mystery objects flying through the sky at high speed.

Published by the To The Stars Academy of Arts & Science (TTSAAS), they include audio from US Fighter pilots expressing amazement at what they were seeing.

Overnight, the US Navy confirmed that, while it is still unsure what the objects are, the leaked footage is real.

Spokesman Joseph Gradisher told NBC News that the objects have been classified as "unidentified aerial phenomena."

"The three videos show incursions into our military training ranges by unidentified aerial phenomena. The Navy has characterised the observed phenomena as unidentified."

TTSAAS said the videos went through a "declassification review process" and were approved for release.

the group is funded by Blink 182 singer Tom DeLonge.

Mr Gradisher said they were never classified. He said the 2004 clip had been widely shared by the crew of the USS Nimitz aircraft carrier and was first posted online in 2007.

He said the navy decided it was too late to pursue the matter after it became aware of the footage.

He said he has "no information" on how the 2015 clips ended up in the public domain.

He said sightings of sightings of "unidentified aerial phenomena" were on the rise.

"Any incursion into our training ranges by any aircraft or phenomena, identified or not identified, is problematic from both a safety and security concern," he said.

He said "unidentified aerial phenomena" phrase had been borrowed from the UK and covers "any aerial phenomenon that cannot immediately be identified."