Some UFO sightings by military personnel are “difficult to explain,” said Gen. Mark A. Milley, chairman of the Joint Chiefs of Staff, but the nation’s top general insists he has seen no evidence to back up public allegations that the Pentagon has recovered extraterrestrial beings or has engaged in decades of cover-ups to hide the truth from the American public.

In an exclusive interview with The Washington Times, Gen. Milley acknowledged that some reports of what the government now calls unidentified aerial phenomena, or UAP, lack easy explanations despite serious, ongoing research inside the Pentagon and a growing belief that at least some of the craft could pose national security threats. He made the comments less than two weeks after former U.S. intelligence officer David Grusch told Congress under oath that he is aware of “a multidecade UAP crash retrieval and reverse-engineering program” and even suggested that the Pentagon has been secretly keeping extraterrestrial bodies in storage.