Story highlights Bob Corker is a Tennessee Republican who was a one-time Donald Trump ally

The senator criticized Trump last week following his Charlottesville response

(CNN) White House press secretary Sarah Huckabee Sanders fired back at Sen. Bob Corker, R-Tennessee, who last week said Trump hasn't demonstrated the "stability" or "competence" he needs to display as president.

"I think that's a ridiculous and outrageous claim that doesn't dignify a response from this podium," Sanders said Thursday, in the White House's first response to the comments.

Corker, who is the chairman of the Senate foreign relations committee, was among the Republicans who leveled biting criticism in the wake of Trump's much-criticized response to the violent protests that broke out after white supremacists rallied in Charlottesville, Virginia.

"The President has not yet been able to demonstrate the stability nor some of the competence that he needs to demonstrate in order to be successful," Corker said last Thursday. "He has not demonstrated that he understands what has made this nation great and what it is today, and he's got to demonstrate the characteristics of a president who understands that."

The criticism was particularly striking coming from Corker, a one-time Trump ally whom the President considered as a candidate for secretary of state.

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