President Trump on Saturday branded Rep. Elijah Cummings, D-Md., a “brutal bully” for his treatment of border patrol officials at committee hearings -- and described Cumming’s district as “far worse and more dangerous” than the southern border.

“Rep, Elijah Cummings has been a brutal bully, shouting and screaming at the great men & women of Border Patrol about conditions at the Southern Border, when actually his Baltimore district is FAR WORSE and more dangerous,” he tweeted Saturday morning.

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Trump was apparently referring to Cummings' questioning of border officials in his role as chairman of the House Oversight Committee. This month, he yelled at acting Homeland Security chief Kevin McAleenan for saying the department was doing its “level best” when it comes to the humanitarian crisis at the border.

"What does that mean? What does that mean when a child is sitting in their own feces, can't take a shower? Come on man,” he yelled. “What's that about? None of us would have our children in that position. They are human beings."

Cummings later questioned whether there was an “empathy deficit,” a remark that appeared to anger McAleenan, who noted the agents make more than 4,000 rescues a year.

The comments may have also angered Trump, who on Saturday said that the detention centers at the border are “clean, efficient and well run, just very crowded.” He then compared that to the conditions in Cummings' district.

“Cumming[s'] District is a disgusting, rat and rodent infested mess. If he spent more time in Baltimore, maybe he could help clean up this very dangerous & filthy place,” Trump tweeted, before calling for an investigation into why Baltimore received so much federal funding.

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“Why is so much money sent to the Elijah Cummings district when it is considered the worst run and most dangerous anywhere in the United States. No human being would want to live there. Where is all this money going? How much is stolen? Investigate this corrupt mess immediately!"

Cummings responded later Saturday, saying it is his constitutional duty to conduct oversight of the Executive Branch: "But, it is my moral duty to fight for my constituents."

"Just yesterday, I held a hearing on the skyrocketing prices of prescription drugs and the financial hardships that families across the nation, and in Baltimore, are facing," he tweeted.

He went on to say that he wanted to address the problem with Trump, and referred to a conversation they had in 2017 about legislation to lower drug prices.

Baltimore Mayor Bernard C. "Jack" Young, meanwhile, said in a statement that it was "completely unacceptable for the political leader of our country to denigrate a vibrant American City like Baltimore, and to viciously attack U.S. Representative Elijah Cummings a patriot and a hero."

"Mr. Trump's rhetoric is hurtful and dangerous to the people he's sworn to represent," he said.

Cummings last week said that there was "no doubt" that Trump is a racist after the president's tweets about the four freshman congresswomen known as "The Squad" and said they should "go back and help fix the totally broken and crime infested places from which they came."

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“When I hear those things, it takes me back,” Cummings said in reference to segregation in the 1960s. Cummings went on to compare the president’s tweets to his own experience in 1960's Baltimore when he tried to integrate a public swimming pool.

“I heard the same kind of chants, ‘Go home, you don’t belong here,’” Cummings said on ABC's "This Week." “I’m not the only person of color who has had those kind of experiences.”