Politico has reported that President Donald Trump is angry because he thinks Republicans have not been forthright enough in defending his incendiary tweets targeting four congresswomen of color.

GOP leaders in the House and the Senate have refused to describe Trump's tweets as racist.

Some Republican lawmakers, however, are breaking ranks to criticize the tweets, including nearly half the delegation from the crucial swing state of Ohio.

On Wednesday, four Republican House members voted in favor of a measure condemning the racist language of Trump's attack.

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President Donald Trump has told at least two Republican lawmakers he is angry about what he believes to be a weak defense among congressional Republicans of his tweets targeting four congresswomen, Politico reported Tuesday.

Multiple sources with direct knowledge of the matter told Politico that Trump was displeased with what he saw as lukewarm GOP support for his racists comments telling the lawmakers of color to "go back and help fix" their "broken and crime infested" countries. Three of the four women were born in the US, and all four are American citizens.

Read more: House of Representatives votes to condemn Trump's 'racist comments' in a remarkable rebuke of the president

Rep. Alexandria Ocasio-Cortez is one of the congresswomen targeted by the president. J. Scott Applewhite/AP

Republican leaders have refused to call Trump's attack racist, with House Minority Leader Kevin McCarthy, a California Republican, on Tuesday saying the dispute was "all about politics and beliefs of ideologies."

Senate Majority Leader Mitch McConnell, of Kentucky, told reporters Tuesday that "the president's not a racist," but when asked how he'd react to his wife, Transportation Secretary Elaine Chao, being told to go back home, he defended legal migration as "good for America."

Some Republicans, though, have broken rank to criticize the president, with four Republicans voting on Tuesday in favor of a House measure condemning the racist language of Trump's tweets.

According to Reuters, three dozen of the 250 GOP lawmakers in Congress have criticized the president, including three from Texas and almost half of the delegation from Ohio, a crucial 2020 battleground state.

Rep. Fred Upton of Michigan was one of four Republicans who voted Tuesday in favor of a motion condemning Trump's tweets. Chip Somodevilla/Getty Images

Read more: Here are the 4 Republicans who voted in the House to condemn Trump's racist comments

Republican lawmakers have generally held back from openly criticizing the president, fearing the public humiliation and attacks he levies against those who speak out against him and cautious about the enormous popularity among supporters of the party.

A poll taken this week by Reuters and Ipsos found that Trump's popularity among Republicans had increased since he sent the inflammatory tweets on Sunday.

Perhaps aware that the controversy might benefit him among his base, Trump has shown no sign of backing down. On Tuesday he stepped up attacks on the congresswomen — Reps. Alexandria Ocasio-Cortez of New York, Rashida Tlaib of Michigan, Ayanna Pressley of Massachusetts, and Ilhan Omar of Minnesota — accusing them of being "pro-terrorist."