
Reports reveal high-speed black triangles over US military sites in newly released documents.
Pentagon files included a sighting of a black triangular object.
Observers described the object flying at 1,800 mph with no exhaust, disappearing silently.
Images in the report are disputed as potentially not offering substantiated evidence.
The release is part of Trump's transparency initiative on UAP documents.
Pentagon's recent release contains limited details.
Further investigations by military and governmental bodies into the nature of UAPs are expected.