U.S. Navy pilots reported encounters with unidentified flying objects in 2014 and 2015, leaked video has revealed.

The clip, obtained by the New York Times, reveals several pilots saw “strange objects” that appeared to be buzzing around at hypersonic speeds — despite having “no visible engines.”

At one point in the video, a pilot can be heard saying he almost hit one of the objects, which he describes as having an appearance of “a sphere encasing a cube.” Lt. Ryan Graves, a 10-year Navy veteran, says the UFOs were “accelerating to hypersonic speed, making sudden stops and instantaneous turns — something beyond the physical limits of a human crew.”

Asked to explain the phenomenon, Navy spokesman Josh Gradisher says simply, “We don’t have enough evidence to track this.”

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