The U.S. Navy famously refrains from talking about UFOs but it is revising its rules for how military pilots report encounters with “unidentified aircraft.”

The changes are intended to ensure that any “suspected incursions” are reported to military authorities, according to Joseph Gradisher, a spokesperson for Vice Admiral Matthew Kohler, the deputy chief of naval operations for information warfare.

“There have been a number of reports of unauthorized and/or unidentified aircraft entering various military-controlled ranges and designated air space in recent years,” Gradisher said in a statement provided to NBC News MACH. The Navy and the Air Force "take these reports very seriously and investigate each and every report," he added.

Gradisher didn’t detail the reports, but there have been some highly publicized ones — including one made public in late 2017 in which pilots flying off the coast of San Diego in 2004 captured video of a wingless, oval-shaped object that appeared to be moving erratically across the sky.

In an interview with Politico, which first reported the changing rules, former Pentagon official Luis Elizondo said the new procedures could encourage pilots to speak up about unusual sightings, particularly if they might normally be wary to do so. Elizondo was head of the Pentagon's now-defunct Advanced Aviation Threat Identification Program, a $22-million initiative to study unusual sightings reported by military pilots, including the 2004 incident near San Diego. The program began in 2007 and ended in 2012.

Seth Shostak, senior astronomer at the SETI Institute in Mountain View, California, said it wasn’t surprising that the military would be keen to make sure that commanding officers are made aware of sightings of unidentified aircraft.

“The government has been interested in this since the 1940s, and always for the same reason: they want to know if these are enemy aircraft,” Shostak said. “That’s still the case here."

The Navy's changing rules are by no means an acknowledgement that alien spacecraft might be among the unidentified aircraft that have been reported, according to Shostak. “There’s always going to be a group of people that leaps to the more interesting conclusion,” he said. “But 90 percent of these sightings turn out to be a laundry list of things like birds, balloons or other aircraft.”

But Shostak praised the Navy for taking steps to ensure that military pilots who report unexplained aircraft don’t "get laughed at."

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