One of the world's leading experts on UFOs has claimed whistleblowers involved in top-secret US government programs have already begun giving testimony as part of a long-awaited review, The U.S. Sun can reveal.

After decades of it being a taboo topic, Congress is finally waking up to UFOs, and the Department of Defense is reviewing historical documents related to "unidentified aerial phenomena" dating back to 1945.

The amendment features in the latest multi-billion-dollar National Defense Authorization Act, which funds the department's annual operating budget.

Last year, the department also set up the All-Domain Anomaly Resolution Office to document UAPs that might pose a threat and to protect anyone wanting to come forward with information.

Nick Pope, who previously worked for the UK's Ministry of Defense investigating the UFO phenomena, spoke exclusively to The U.S. Sun during Alien Con, an annual expo held in Pasadena, California.

He said: "Congress has put on the US government to go back to January 1, 1945, and report on anything that they've done, from then moving forward.

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