U.S. President Donald Trump would make a "terrible mistake" if he pardoned his former campaign chairman, Paul Manafort, after charges brought as a result of the federal probe into Russian election interference, Republican Sen. Marco Rubio said on Sunday.

"I just think it would be the wrong thing to do and I think it would be a huge political mistake as well," Rubio said on CNN's "State of the Union."

Manafort faces sentencing on his convictions in August of tax and bank fraud charges. In a court filing on Friday, special counsel Robert Mueller said Manafort lied to investigators about his interactions with a Russian tied to Russian intelligence services.