WASHINGTON – In another sign of deepening divisions within the Republican party, President Trump blasted two sitting GOP senators who have criticized his response to the Charlottesville attack – whose support he needs to get his agenda through Congress.

In a flurry of tweets, Trump also defended the presence of Confederate monuments. "You can't change history, but you can learn from it," he said in one tweet. "Robert E Lee, Stonewall Jackson - who's next, Washington, Jefferson? So foolish!"

The white supremacists who gathered at the "Unite the Right" rally in Charlottesville last weekend said they were there to protest the city's plans to remove a Robert E. Lee statue.

Earlier, Trump used Twitter to go after Sen. Lindsey Graham, saying the South Carolina senator falsely accused him of offering "moral equivalency" between the KKK, neo-Nazis, and and other white supremacist groups who counter-protested the hate groups.

"Such a disgusting lie," Trump tweeted. "He just can't forget his election trouncing.The people of South Carolina will remember!"

Trump made a more explicit threat to back a primary challenger for Arizona Sen. Jeff Flake, praising the latter's Republican primary opponent, who has expressed support for the president.

"Great to see that Dr. Kelli Ward is running against Flake Jeff Flake, who is WEAK on borders, crime and a non-factor in Senate," Trump tweeted. "He's toxic!"

Flake has also written a book criticizing Trump, saying his views and behavior are undercutting the Republican Party and its conservative philosophy.

Trump is still facing a political firestorm for doubling down on Tuesday on his claims that "both sides" were at fault for the violence last weekend in Charlottesville, even after one alleged white nationalist was charged with murder after ramming his car into a crowd of protesters, killing a 32-year-old Heather Heyer.

Yet in a raucous press conference on Tuesday, Trump said that left wing groups were just as violent as white supremacists and declined to say whether one was worse than the other. "You had a group on one side that was bad and you had a group on the other side that was also very violent," Trump said. "And nobody wants to say that. But I’ll say it right now."

Many Republican lawmakers – including Graham and Flake – have distanced themselves from Trump's remarks, pointing out that white supremacist groups came armed with guns, torches, and Nazi flags, chanting racist and anti-Jewish slogans.

After Trump's remarks, Flake said there were no excuses for white supremacy.

In a statement to CNN, Graham cited Heyer and her mother as among those who opposed the white supremacist march.

"Through his statements yesterday, President Trump took a step backward by again suggesting there is moral equivalency between the white supremacist neo-Nazis and KKK members who attended the Charlottesville rally and people like Ms. Heyer," Graham said.

Graham has also been a frequent critic of Trump. While Graham did mount a presidential campaign in 2016, he dropped out well before the South Carolina primary that Trump won.

If the president now wants to back a primary challenger to Graham, he will have to wait: The South Carolina senator isn't up again until 2020.

Trump, who also said this week that "racism is evil" and condemned the KKK and neo-Nazis, also attacked news coverage during his tweet storm.

"The public is learning (even more so) how dishonest the Fake News is," the president tweeted. "They totally misrepresent what I say about hate, bigotry etc. Shame!"

To this, Massachusetts Democratic Rep. Katherine Clark noted cable news carried the remarks live.

In his criticism of Confederate statue removal, Trump contradicted his earlier statement that these kinds of decision should be up to the "local town, community or the federal government" that put up the monuments in the first place.

On Thursday, the president tweeted that "the beauty that is being taken out of our cities, towns and parks will be greatly missed and never able to be comparably replaced!