More whistleblowers in the Pentagon have come forward with 'first-hand knowledge' of secret UFO crash retrieval programs, US Senator Marco Rubio has revealed.

The Republican Florida Sen said officials with 'very high clearances' who have occupied 'high positions within our government' have come forward with 'first-hand knowledge or first-hand claims' of top secret Government programs.

Ex-Air Force officer David Grusch made worldwide news earlier this month when he claimed alien craft and bodies had been recovered and back-engineered by US officials.

Grusch noted that these beings are cautiously described as 'non-human intelligences' by insiders within these highly classified programs, because even experts can't say for sure where these beings really come from. 

Sen. Rubio said that some of these witnesses who spoke with the Senate Intelligence Committee — where Rubio is vice chairman — were likely some of the same individuals referenced by Grusch.

'A lot of these people came to us even before these protections were in the law for whistleblowers to come forward,' Rubio told NewsNation Monday.

Grusch, an Air Force veteran who went on to posts at both the National Geospatial-Intelligence Agency (NGA) and the NRO, told the inspector general that he had faced illegal retaliation for his inquiries into these same highly classified UFO programs.