Editor’s note: This article by Travis Tritten originally appeared on Military.com, a leading source of news for the military and veteran community.

Nearly 250 service members reported seeing UFOs since the spring of 2021 and many of those incidents remain unexplained, according to a joint report released by the Pentagon and intelligence community.

The figures are part of the latest update mandated by Congress after interest in UFOs -- now called unidentified aerial phenomena, or UAP -- surged to its highest point since the 1960s following military videos captured by Navy personnel leaked in 2017 showing unknown objects.

But for anyone looking for extraterrestrials, or even Chinese spying, the 12-page unclassified report will likely be a letdown. Of the 195 cases the Pentagon has solved, the vast majority turned out to be balloons -- 163 in all -- along with a couple of dozen or so drones and some sky garbage, often referred to as airborne clutter.

Of the 171 cases that remained unexplained, "some of these uncharacterized UAP appear to have demonstrated unusual flight characteristics or performance capabilities, and require further analysis," the report said.

More detailed classified assessments of the cases are being provided to Congress.

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"Today's report reflects a step forward in understanding and addressing risks to aviators," Sen. Mark Warner, D-Va., the chair of the Senate Intelligence Committee who sponsored the reporting legislation, said in a released statement. "Overall, I am encouraged to see an increase in UAP reporting -- a sign of decreased stigma among pilots who are aware of the potential threat that UAPs can pose."

A majority of the new 247 incidents were observed by Navy and Air Force aviators and operators. The uptick in the number of troops reporting sightings -- the intelligence community had originally collected 144 cases reported over the previous 17 years -- was due to a better understanding of the threats UFOs pose and the reduced stigma around acknowledging the sightings, according to the report.

The UFOs can create flight hazards in military airspace, if they're things like airborne clutter or balloons, and raise the possibility of spying or other nefarious activity by U.S. adversaries, if they're drones or other reconnaissance aircraft. The leaked military videos and witness accounts that triggered Washington's newest fascination with UFOs all came from military training off the East and West coasts.

"It is clear that there is an urgent and critical need to improve aerospace safety by dedicating scientific research into UAP," Ryan Graves, a former Navy F/A-18 pilot who shared his accounts of UFO encounters off the East Coast with The New York Times and "60 Minutes," said in a statement.

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So far, there have been no collisions, the report says, and no observers have reported any health problems following an incident. Congress' legislation on UFO reporting required a look at health effects, though it's unclear why.

But the appearance of a high number of UFOs in controlled airspace might also be at least partly a misperception, and the objects could be common elsewhere too.

"We continue to assess that this may result from a collection bias due to the number of active aircraft and sensors, combined with focused attention and guidance to report anomalies," according to the report, which was co-written by the Pentagon and released by the Office of the Director of National Intelligence.

Many cases appear to have been solved as the Pentagon has increased its scrutiny of the phenomenon. When Congress held its first UFO hearing in 50 years in May, officials from the Pentagon and intelligence community said a video circulating that showed what appeared to be green triangles floating above a Navy ship actually showed drones.

The triangular shapes touted by UFO enthusiasts were simply a common reflection of the camera lens called bokeh.

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And many of the remaining unexplained cases disclosed for the first time in the new report may never be solved because there just isn't enough information to make a call. "Regardless of the collection or reporting method, many reports lack enough detailed data to enable attribution of UAP with high certainty," the report said.

The push to report military UFO cases was triggered after a group of former Pentagon and government officials leaked Navy videos of unknown objects to The New York Times and Politico in 2017.

At least part of the former officials' alleged evidence came from a secret Pentagon program in 2008 that looked into paranormal phenomena at Skinwalker Ranch in Utah -- now famous as the location of a reality TV show -- and elsewhere, including alleged sightings of werewolves in Virginia. The unusual, short-lived program collected evidence on UFO sightings by the USS Nimitz strike group in 2004.

In July, the Pentagon created the All-Domain Anomaly Resolution Office, which became the clearinghouse for all military UFO encounters, taking over from a department task force. Reports of incidents are to be collected from troops and sent to the office, known as AARO.

"So by establishing those reporting procedures, what it does -- and I think you'll see this in the report -- is it allows the collection of data, and more data allows us to be a little bit more rigorous in terms of how we go after investigating these incidents," Brig. Gen. Pat Ryder, the Pentagon's top spokesman, told reporters during a public briefing.

The report said the Pentagon and intelligence community will continue to investigate whether foreign governments may be involved in the uptick in UFO incidents.