Republican Sen. Bob Corker had strong words for President Trump in his deep red state of Tennessee on Thursday, saying the president has not demonstrated he possesses the stability, competence or understanding of the country's character he needs to succeed.

Speaking to reporters after a rotary club speech in Chattanooga, the chairman of the Senate Foreign Relations Committee said "radical changes" must take place in regards to Mr. Trump. Corker's comments are some of the strongest any Republican has made in recent days, amid the political fallout from Mr. Trump's unscripted remarks Tuesday in which he said "both sides" were to blame for the deadly violence in Charlottesville, Virginia.

Republican Sen. Bob Corker of Tennessee

Corker's comments are particularly noteworthy given that he is up for reelection in 2018 in a state where Mr. Trump carried 91 of 95 counties in 2016.

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"I do think that there do need to be radical changes," Corker told reporters. "The president has not yet been able to demonstrate the stability nor some of the competence that he needs to demonstrates in order to be successful. And we need for him to be successful, our nation needs for him to be successful. It doesn't matter whether you are Republican or Democrat. We need for our president, the world needs our president to be successful."

"He has also recently not demonstrated that he understands the character of this nation," Corker added. "He has not demonstrated that he understands what makes this nation great and what it is today. He has got to demonstrate the characteristics of a president who understands that. And without the things I just mentioned happening our nation is going to go through great peril."

Corker said the president needs to take stock of his role in the country, and move beyond his own interests.

"I will say where there needs to be radical changes take place at the White house itself," Corker said. "It has to happen. I think the president needs to take stock of the role that he plays in our nation and move beyond himself. Move way beyond himself and move to a place where daily he's waking up and thinking about what's best for our nation."

Corker also defended his Republican colleague Sen. Jeff Flake, R-Arizona, after the president took to Twitter earlier in the day to attack him. The president is supporting Flake's primary challenger.

"Senator Flake is one of the finest human beings I've ever met," Corker said. "The White House would be well served to embrace the character, the substance of someone like Senator Flake. One of the finest people I serve with. He's got a conscience. He is a real conservative. And I have the utmost of praise for him. I love serving with him. I hope for the good of the country he'll be someone serving our country after 2018 and I'm thankful to know him."

CBS News' Alan He contributed to this report.