Washington (CNN) Republican senators are fighting back against President Donald Trump's Wednesday morning tweet asking that Attorney General Jeff Sessions end the special counsel Robert Mueller's Russia investigation.

Senate Majority Whip John Cornyn, a Texas Republican, said Sessions doesn't have the authority to end the probe but added the "President is entitled to speak his mind."

"I think that's out of Jeff Sessions' hands," he said. "He's recused himself from the Russian investigation so he really doesn't have any power to stop the Manafort prosecution. It's in court, the jury's been selected and it's going forward."

Trump on Wednesday said Sessions should end Mueller's investigation into Russian election interference, arguing that the ongoing probe is hurting the United States.

Although the President has repeatedly criticized the investigation and Sessions' decision to recuse himself from overseeing it, Trump's tweet that his attorney general "should stop" the probe is notable and raises fresh questions about whether the President is attempting to obstruct justice.

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