Donald Trump has shared a tweet from the far-right commentator Katie Hopkins describing the city represented by a congressman he has repeatedly attacked as a “s***hole”.
The president followed up the retweet with another attack on Elijah Cummings, who represents Baltimore, claiming there was "nothing racist" about his attacks on the congressman.
He said: "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!"
The phrase used by Ms Hopkins is similar to one attributed to Mr. Trump when he reportedly referred to immigrants coming from "s***hole countries" during a White House meeting.
The president has denied that he ever used that phrase.
Mr. Trump caused outrage on Saturday when he claimed Mr. Cummings represented a "rat and rodent infested" district in a series of vicious tweets.
House speaker Nancy Pelosi denounced the president's tweets and said Democrats would "all reject racist attacks against [Mr. Cummings]".
Baltimore's mayor, Bernard C “Jack” Young, said it was “completely unacceptable” for Mr. Trump to “denigrate a vibrant American City like Baltimore” and called the president “a disappointment… to the world.”
Trump attacks black congressman for second day in a row
Mr. Trump was criticized earlier this month when he retweeted a video by Ms. Hopkins supporting his racist attacks on four US congresswomen.
In addition, he retweeted an attack by the far-right commentator on Sadiq Khan, the mayor of London, with a personal comment added: “With the incompetent Mayor of London, you will never have safe streets!”
On Sunday, Ms Hopkins also went after CNN host Victor Blackwell, who emotionally defended his hometown in a speech that has since been shared thousands of times.
She accused the news anchor of "turning on the water-works" during his condemnation of Mr Trump's tweets.
Ms Hopkins, who once held jobs as a controversial columnist and radio host for the Daily Mail, The Sun and LBC, is a prominent supporter of jailed anti-Islam activist Tommy Robinson.
In September last year, she applied for an insolvency agreement in a last-ditch attempt to avoid bankruptcy after she lost a libel case to food writer and poverty campaigner Jack Monroe.