Washington (CNN) Outgoing Sen. Bob Corker slammed President Donald Trump after his handling of the racially motivated violence in Charlottesville, Virginia, in August, and he's standing by those words.

Days after Trump blamed "both sides" for the fatal violence, which blew up after white supremacists held a march to protest the city's planned removal of a statue of Confederate Gen. Robert E. Lee, the Tennessee Republican didn't mince words.

"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," he said.

Asked about the remarks in an interview on NBC's "Meet the Press" that aired Sunday, Corker said he did not regret them.

"I stand by those words," Corker told moderator Chuck Todd, adding that he visited the White House recently and spoke about it with Trump.

"When I met with the President a week ago Friday, I said, 'Mr. President I stand by what I said,'" Corker said.

Trump's response was "kind of humorous," Corker said, adding that he was able to explain what he meant.

"In five minutes, we moved on," Corker said.

In the interview, Corker praised the leadership of former Gen. John Kelly, who joined the White House as chief of staff in July. But the senator maintained that the President still has not shown the kind of stability he needs to show.

Corker, who chairs the Foreign Relations Committee, said he has seen some changes in the way the White House is operating and praised Trump for changing his position on Afghanistan and committing the US to a troop increase there. He forecast that the US military would still be in the nation, which the US invaded in 2001 to oust the Taliban, well after he leaves Congress.

"Are we likely to have troops in Afghanistan for the next decade? Sure," Corker said.

Corker announced his retirement on Tuesday, which came as a blow to Senate Republican leadership and sets the stage for what could be a fierce primary race in Tennessee.

Corker anticipated he would have a strong impact on US policy in his remaining months in office as the Republican Party seeks to push through major agenda items before the midterm elections.

He pledged to take varying analysis in to consideration on the Republicans' proposed tax overhaul, but said he remains concerned about the national debt and would not sign onto a plan that would increase the nation's borrowing.

"If it looks like to me, Chuck, we're adding one penny to the deficit, I am not going to be for it," Corker said.