This file photo taken on Feb. 19, 2020 shows the Pentagon seen from an airplane over Washington, D.C., the United States. (Xinhua/Liu Jie)

The files were compiled by multiple U.S. agencies, including the State Department, the Defense Department, NASA, the FBI, and U.S. diplomatic missions overseas.

by Xinhua writer Tan Jingjing

LOS ANGELES, May 8 (Xinhua) -- The Pentagon on Friday began the release of "never-before-seen" files on unidentified anomalous phenomena (UAP), commonly known as unidentified flying objects (UFOs).

The files are being housed on a government website, war.gov/UFO. Additional materials will be released on a rolling basis, according to a press release from the U.S. Department of Defense.

A total of 161 files are currently accessible on the website, including photos, videos, official documents and eyewitness accounts.

The documents detail more than 400 UAP-related incidents reported around the world, spanning from the 1940s to recent years.

The files were compiled by multiple U.S. agencies, including the State Department, the Defense Department, NASA, the FBI, and U.S. diplomatic missions overseas.

"The American people can now access the federal government's declassified UAP files instantly. The latest UAP videos, photos, and original source documents from across the entire United States government are all in one place -- no clearance required," the Defense Department said in the release.

According to the department, the archived materials involve "unresolved cases," meaning the government is unable to make a definitive determination on the nature of the observed phenomena, noting that such uncertainty can result from a variety of factors, including insufficient data.

It added that while all the materials had undergone security review, many had not yet been fully analyzed to determine the nature of the reported anomalies.

The public "can ultimately make up their own minds about the information contained in these files," the department said.

NASA Administrator Jared Isaacman said the agency would continue to rely on scientific research and data analysis in studying such phenomena.

"We will remain candid about what we know to be true, what we have yet to understand, and all that remains to be discovered," Isaacman said.

Among the newly released materials are records related to the Apollo 11, Apollo 12 and Apollo 17 lunar missions.

Astronauts from Apollo 17 reported observing "very bright particles or fragments" drifting and tumbling near their spacecraft. The astronauts speculated that the phenomenon might be attributable to ice or paint fragments dislodging from a separated component of the spacecraft but characterized that assessment as a "wild guess."

According to the Defense Department, the disclosure follows U.S. President Donald Trump's directive to begin identifying and declassifying government files related to UAP.

In recent years, the U.S. Congress has held multiple hearings on UAP, while military videos, pilot reports and disclosures by former intelligence officials have continued to draw public attention.

At the same time, the U.S. government has stepped up monitoring efforts related to drones, unidentified aircraft and airspace security, with UAP increasingly being incorporated into a broader national security and technological surveillance framework.

The released files show no indication that the U.S. government has had any interaction with beings from other planets or that it has any reason to believe such beings have visited Earth, NBC News reported.