WASHINGTON - Democratic House speaker Nancy Pelosi has accused US President Donald Trump of "racist attacks" in his tweets about an African-American lawmaker.
Mr Trump attacked Democratic Rep Elijah Cummings and his Maryland district on Twitter.
The president described Mr Cummings' majority-black district in Baltimore as a "rodent-infested mess".
Mr Cummings was a "bully", Mr Trump wrote, for criticising the treatment of migrants at the US-Mexico border.
As chairman of the House Oversight Committee, Mr Cummings has instigated a series of investigations into the Trump administration's policies, including its handling of migrants at detention centres.
Ms Pelosi led Democratic legislators in defending Mr Cummings and condemning Trump's tweets.
The tweets, Ms Pelosi wrote, were "racist attacks" on Mr Cummings, whose district's population is more than 50% black according to US census data.
President Trump's remarks come just weeks after he was criticised for another tweet telling "'progressive' Democrat congresswomen" to "go back" to the "crime infested" places they came from.
The message was aimed at four lawmakers of colour - Alexandria Ocasio-Cortez, Rashida Tlaib, Ayanna Pressley, and Ilhan Omar - all of whom are US citizens.
Last week, Mr Cummings lashed out at acting Homeland Security Secretary Kevin McAleenan and conditions at migrant detention centres at a congressional hearing.
In a heated exchange with Mr McAleenan, Mr Cummings demanded "improvement" at border facilities.(FA)