More than 120 retired U.S. military leaders have signed an open letter appearing to advance a false conspiracy theory that the 2020 election was rigged and questioning President Joe Biden’s mental capacity to serve.

“Without fair and honest elections that accurately reflect the ‘will of the people’ our Constitutional Republic is lost,” said the letter released Tuesday by “Flag Officers 4 America,” and signed by 124 former admirals and generals.

“The FBI and Supreme Court must act swiftly when election irregularities are surfaced and not ignore them as was done in 2020.”

On its website, Flag Officers 4 America says it is a collection of “retired military leaders who pledged to support and defend the Constitution of the U.S. against all enemies, foreign and domestic.”