President Trump ranted Saturday morning on Twitter about an African American lawmaker by disparaging the Baltimore district that Rep. Elijah E. Cummings (Md.) represents as a “disgusting, rat and rodent infested mess.”

As chairman of the House Oversight and Reform Committee, Cummings has initiated most of the investigations into the Trump administration’s operations and policies, including recently the reports of inhumane treatment at migrant detention centers.

Trump, seemingly borrowing from a Fox & Friends segment on the same topic, tweeted that Cummings’s district is “FAR WORSE and more dangerous” than conditions at the border. He suggested Cummings focus his attention instead on cleaning up “this very dangerous & filthy place.”

Trump’s attack on Cummings is reminiscent of his recent racist attacks on four minority congresswomen who he said should “go back” to the “crime infested” places they were originally from and fix them before trying to improve America. All four women are U.S. citizens, and only one was born abroad.

In a series of three tweets, Trump wrote:

“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. His district is considered the Worst in the USA......

. . . As proven last week during a congressional tour, the Border is clean, efficient & well run, just very crowded. Cumming 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.

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 a few hours later, defending his dedication to his constituents and pivoting to Trump’s failure to work with him on lowering drug prices.

“Mr. President, I go home to my district daily. Each morning, I wake up, and I go and fight for my neighbors,” Cummings tweeted. “It is my constitutional duty to conduct oversight of the Executive Branch. But, it is my moral duty to fight for my constituents.”

An hour before Trump went off on Cummings, Fox & Friends ran a piece called, “How do living conditions in Rep. Cummings’ Baltimore district compare to those at the border?” It showed footage of Baltimore streets overrun with garbage and claimed that Cummings was ignoring the problems of his own constituents.

Baltimore is the third most dangerous city in the country behind Detroit and St. Louis, according to the FBI’s 2017 crime report. But Maryland’s 7th district, which Cummings has represented since 1996, includes about half of Baltimore city and has a median household income of around $60,000 and a higher percentage of college graduates than the country as a whole.

Baltimore Mayor Bernard C. Young released a statement defending both Cummings and his city, calling the president a “disappointment to the people of Baltimore, our country and to the world.”

“It’s 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,” he said. “Mr. Trump’s rhetoric is hurtful and dangerous to the people he’s sworn to represent.”

Trump isn’t the first politician to comment on Baltimore’s struggles, but others have done so from a position of wanting to help.

In 2016, Sen. Bernie Sanders (I-Vt.), then fighting Hillary Clinton for the Democratic nomination for president, took a walking tour of an impoverished Baltimore neighborhood. He said it looked like a “Third World country,” as he decried America’s vast economic inequality.

Notably, Ben Carson, the only black member of Trump’s Cabinet, made his career as a neurosurgeon in Baltimore. A spokesman at the Department of Housing and Urban Development, which Carson now leads, did not immediately respond to a request for comment.

Sen. Kamala D. Harris (D-Calif.), whose 2020 presidential campaign headquarters is in Baltimore, tweeted that she’s “proud” to have it based there.

“Baltimore has become home to my team and it’s disgraceful the president has chosen to start his morning disparaging this great American city,” she wrote.

Many other Democrats rushed to Cummings’s defense. Former vice president Joe Biden, also a presidential candidate, said the Maryland congressman “is one of the finest people I’ve served with.”

“It is despicable for you to attack him and the people of Baltimore this way,” Biden tweeted. “Once again you have proved yourself unfit to hold the office. A President is supposed to lift this nation up. Not tear it down.”

Trump’s tweets and the Fox News report seem to be in response to a July 18 hearing, at which Cummings became furious when acting homeland security secretary Kevin McAleenan said his department was doing its best with a difficult situation.

“When a child is sitting in their own feces, can’t take a shower? . . I want to concentrate on these children, and I want to make sure that they’re okay . . . We are the greatest country in the world,” Cummings bellowed. “Come on. We’re better than that.”

But the president’s ire with Cummings may also have to do with the chairman securing permission from his committee this week to subpoena all emails and texts dealing with official government business sent to or from administration officials on their personal accounts, which would include communications to and from the president’s daughter and adviser Ivanka Trump and her husband, Jared Kushner, who reportedly have used private emails to carry out White House work.

House Speaker Nancy Pelosi, whose father, Thomas D’Alesandro Jr. was a U.S. congressman representing parts of Baltimore and then the mayor of the city, forcefully defended Cummings, calling him “a champion in the Congress and the country for civil rights and economic justice, a beloved leader in Baltimore, and deeply valued colleague.”

“We all reject racist attacks against him and support his steadfast leadership. #ElijahCummingsIsAPatriot,” Pelosi (D-Calif.) tweeted.

Sen. Chris Van Hollen (D-Md.), who served in the House alongside Cummings for many years, also tweeted praise for his colleague and condemned the president.

“Elijah Cummings grew up facing racist bullies like Trump and learned to confront them with qualities unknown to Trump: courage and integrity,” Van Hollen wrote. “The great people of Baltimore have something Trump craves but will never have as he degrades the Office of the President: dignity.”

In an emotional monologue about Trump’s latest comments, CNN’s Victor Blackwell pointed out that Trump has often used the word “infested” to refer to places where black and brown people live. To Trump’s contention that “no human being” would want to live in Baltimore, Blackwell said, his eyes filled with tears, that he did.

“I don’t want to sound self-righteous, but people get up and go to work there,” he said. “They care for their families there. They love their children who pledge allegiance to the flag just like people who live in districts of congressmen who support you, sir. They are Americans, too.”

Responses on social media included tweets from Michelle Obama and Jenna Bush Hager.

The former first lady tweeted a video of her watching a performance by a Baltimore student dance team two years ago: “On #NationalDanceDay, I’m shouting out the Lethal Ladies, a Baltimore STEP team who I saw perform back in 2017. I’m so proud of you all — and everyone who’s dancing today!”

Hager, the daughter of President George W. Bush, retweeted a video clip of Blackwell’s monologue and added: “I taught in West Baltimore. I adore my kids, their parents, and grandparents. They all want the same thing I want for my kids: the chance for their children to have safe, happy and productive lives. Let’s think about the language we use, who it hurts.”