TASS writes about this with reference to the corresponding report of the Office for Resolving Anomalies in All Areas (AARO). 

The document states that reports of unidentified flying objects (UFOs) and suspected alien craft were actually the result of misidentification by eyewitnesses.

The report also notes that investigations, which were conducted under various levels of secrecy, showed that most “UFO sightings” involved ordinary objects or phenomena.

Previously, the outgoing Pentagon director of anomalies Sean Kirkpatrick did not rule out the extraterrestrial nature of UFOs.