WASHINGTON — Facing growing accusations of racism over his incendiary tweets, President Donald Trump on Sunday tried to deflect the criticism by labeling a prominent minority congressman as himself racist and accusing Democrats of trying to "play the race card."

Trump assailed Rep. Elijah Cummings, D-Md., as a racist after the president's criticisms of the congressman's majority-black district in the Baltimore area as a "rodent-infested mess" where "no human being would want to live" drew widespread condemnation from Democrats as race-baiting.

Trump insisted there was nothing racist about his criticism and tweeted back, "If racist Elijah Cummings would focus more of his energy on helping the good people of his district, and Baltimore itself, perhaps progress could be made in fixing the mess that he has helped to create over many years of incompetent leadership."

"His radical 'oversight' is a joke!" Trump added. He offered no detail to back up his accusation of racism against Cummings.

The president's comments capped a weekend of attacks on Cummings, the powerful chairman of the House Oversight and Reform Committee, and marked his latest rhetorical shot against non-white lawmakers, exacerbating racial tensions. Two weeks ago, Trump caused a nationwide uproar with racist tweets directed at four Democratic congresswomen of color.

Heading into the 2020 elections, the president is trying to tap into anxieties about demographic and cultural changes in the nation in the belief that the divided country he leads will simply choose sides over issues such as race.

A White House aide said Sunday that Trump was frustrated by the Democrats' unrelenting investigations and talk of impeachment and swung hard at Cummings and his district because the president believes such Capitol Hill critics are neglecting serious problems at home in their zeal to undermine his presidency.

Acting chief of staff Mick Mulvaney insisted in two national television interviews that Trump was not making racist comments. But Mulvaney, a former congressman himself, said he understood why some people could perceive Trump's words as racist.

Mulvaney said Trump's words were exaggerated for effect — "Does the president speak hyperbolically? Absolutely" — and meant to draw attention to Democratic-backed investigations of the Republican president and his team in Washington.

"Instead of helping people back home, they're focusing on scandal in Washington D.C., which is the exact opposite of what they said they would do when they ran for election in 2018," Mulvaney said, pointing at Democrats who now control the House.

He asserted that Trump's barbs were a reaction to what the president considered to be inaccurate statements by Cummings about conditions in which children are being held in detention at the U.S.-Mexico border.

At a hearing last week, Cummings accused a top administration official of wrongly calling reports of filthy, overcrowded border facilities "unsubstantiated."

"When the president hears lies like that, he's going to fight back," Mulvaney said.

Democratic presidential candidate Julián Castro countered that Trump was engaging in "racial priming."

"Using this language and taking actions to try and get people to move into their camps by racial and ethnic identity. That's how he thinks he won in 2016 and that's how he thinks he's going to win in 2020," Castro said.

Trump's tweets Saturday also charged that Cummings' district, which includes Johns Hopkins Hospital, the Social Security Administration and the national headquarters of the NAACP, is "considered the worst run and most dangerous anywhere in the United States."

Condemnation followed from Democrats over the weekend, including some of the party's presidential candidates. Statements from a spokesman for Maryland's Republican governor and from the lieutenant governor defended Cummings' district and its people.

Trump, unbowed, resumed the verbal volleying Sunday: "There is nothing racist in stating plainly what most people already know, that Elijah Cummings has done a terrible job for the people of his district, and of Baltimore itself. Dems always play the race card when they are unable to win with facts. Shame!"

Mulvaney argued that Trump would criticize any lawmaker, no matter the person's race, in a similar way if Trump felt that individual spoke unfairly about the president's policies.

To Mulvaney, Trump was "right to raise" the challenges faced in Cummings' district at the same time that Cummings and other Democrats are "chasing down" the Russia investigation undertaken by Robert Mueller and pursuing "this bizarre impeachment crusade."

Nonetheless, the chief of staff said he understood why some people view Trump's comments as racist, "but that doesn't mean that it is racist."

"The president is pushing back against what he sees is wrong," he added. "It's how he's done it in the past and he'll continue to do it in the future."

Cummings is leading multiple investigations of the president's governmental dealings. In his direct response to Trump on Twitter, Cummings said: "Mr. President, I go home to my district daily. Each morning, I wake up, and I go and fight for my neighbors. It is my constitutional duty to conduct oversight of the Executive Branch. But, it is my moral duty to fight for my constituents."

Cummings has also drawn the president's ire for investigations touching on his family members serving in the White House. His committee voted along party lines Thursday to authorize subpoenas for personal emails and texts used for official business by top White House aides, including Ivanka Trump and her husband, Jared Kushner.

Earlier this month, Trump drew bipartisan condemnation following his call for Democratic Reps. Ilhan Omar of Minnesota, Alexandria Ocasio-Cortez of New York, Ayanna Pressley of Massachusetts and Rashida Tlaib of Michigan to get out of the U.S. "right now." He said that if the lawmakers "hate our country," they can go back to their "broken and crime-infested" countries.

All four lawmakers of color are American citizens and three of the four were born in the U.S. The House later voted largely along party lines to condemn his "racist comments."

Cummings' district is about 55% black and includes a large portion of Baltimore. The city has struggled with violent crime, with more than 300 homicides for four years in a row. It has crumbling infrastructure and a police department under federal oversight.

Mulvaney was interviewed on "Fox News Sunday" and CBS' "Face the Nation," where Castro also appeared.