Story highlights Tom Coburn endorsed the Florida Republican senator in a statement Monday, the day before Oklahoma votes in its primary.

Calling his campaign a "fabrication," Coburn said Trump "is perpetuating a fraud on the American people."

Washington (CNN) Marco Rubio picked up another high-profile endorsement Monday, this time from former Oklahoma Sen. Tom Coburn -- who slammed front-runner Donald Trump for "fraud."

Coburn endorsed the Florida Republican senator in a statement Monday, the day before Oklahoma votes in its primary.

He had harsh words for Trump, mirroring Rubio, who has also sharpened his attacks on the mogul.

Calling his campaign a "fabrication," Coburn said Trump "is perpetuating a fraud on the American people. His empty promises, bullying and bloviating rhetoric will only deepen the frustration and disillusionment that gave rise to his campaign. He simply lacks the character, skills and policy knowledge to turn his grandiose promises into reality."

It's the latest big name endorsement for the Florida senator, who has locked up support from much of the Republican Party's establishment names. In Oklahoma, one of a dozen states voting on Super Tuesday, Rubio also has the support of Sen. Jim Inhofe, Rep. Markwayne Mullin and former Gov. Frank Keating.

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