Congress is asking all your burning questions about UFOs.

A U.S. House Intelligence subcommittee held Congress’ first hearing on unidentified aerial phenomena, or UAP, in more than half a century on Tuesday, and intelligence officials said they’ve collected about 400 reports of UAP.

Scott Bray, deputy director of naval intelligence, said military reports of unidentified phenomena in the military are up, which he attributed in part to reduced stigma in reporting sightings.

“Since the early ‘00s we have seen an increasing number of unauthorized and or unidentified aircraft or objects in military-controlled training areas and training ranges and other designated airspace,” Bray said. “Reports of sitings are frequent and continuing.”

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The military now has step-by-step protocol for how to report a sighting, he said.

“If you see something, you need to report it,” he said.

Some phenomena end up having an explanation, including “aerial clutter” like balloons, drones, some sort of natural phenomenon, or something from a U.S. developmental program or foreign adversary.

During the hearing, footage was shown of one areal phenomenon that remains unexplained and another they later likely concluded was drones.

The first video, shot from a U.S. Navy aircraft, showed something briefly zooming across the screen. The second video, shot through night-vision goggles, showed triangles in the air they later concluded were likely drones, or “unmanned aerial systems in the area,” Bray said.

The U.S. Navy UAP task force also has non-military reports, and it’s not just the U.S. that has observed things in the sky it can’t explain, Bray said. Allies also have their own sightings, and China is also investigating the phenomena, he said. The task force also has relationships with other U.S. entities to rule out any explanations that UAP are actually American.

Bray said the U.S. was “not aware of any adversary that can move an object without discernible means of propulsion,” and that the UAP task for doesn’t have any wreckage “that isn’t consistent with being of terrestrial origin.”

“I would simply say there are a number of events in which we do not have an explanation,” he said. “We make no assumptions about the origin of this or that there may or may not be technology we don’t understand.”

He said U.S. intelligence hasn’t always been open about what it knows, because of U.S. adversaries.

“Given the nature of our business, national defense, we’ve had sometimes to be less forthcoming with information in open forums than many would hope,” he said. “If UAP do indeed represent a potential threat to our security, then the capabilities, systems, processes, and sources we use to observe, record, study or analyze these phenomena need to be classified at appropriate levels.”

“We do not want potential adversaries to know exactly what we’re able to see or understand, or how we come to the conclusions we make,” Bray added.

Ronald Moultrie, the undersecretary of defense for intelligence and security, said during the hearing that the task force is committed to finding answers for the safety of U.S. pilots, not to mention to satisfy inquisitive relatives.

“We want to know what’s out there as much as you want to know what’s out there,” Moultrie said. “We get the questions not just from we, we get them from family members.”