(CNN) -- All 10 living former US defense secretaries declared that the US presidential election is over in a forceful public letter published in The Washington Post on Sunday as President Donald Trump continues to deny his election loss to Joe Biden.

The letter -- signed by Dick Cheney, James Mattis, Mark Esper, Leon Panetta, Donald Rumsfeld, William Cohen, Chuck Hagel, Robert Gates, William Perry and Ashton Carter -- amounts to a remarkable show of force against Trump's subversion efforts just days before Congress is set to count Electoral College votes.

"Our elections have occurred. Recounts and audits have been conducted. Appropriate challenges have been addressed by the courts. Governors have certified the results. And the electoral college has voted. The time for questioning the results has passed; the time for the formal counting of the electoral college votes, as prescribed in the Constitution and statute, has arrived," the group wrote.