WASHINGTON — U.S. Sen. Pat Toomey on Monday became one of the few Republicans to criticize President Donald Trump’s tweets assailing four Democratic members of Congress — all women of color — and urging them to “go back” to the countries they came from.

“Three of the four were born in America and the citizenship of all four is as valid as mine,” Toomey, the Pennsylvania Republican, said in a statement. "I couldn’t disagree more with these congresswomen’s views on immigration, socialism, national security, and virtually every policy issue. But they are entitled to their opinions, however misguided they may be. We should defeat their ideas on the merits, not on the basis of their ancestry.”

A full day after Trump unleashed the tweets that were widely condemned as racist, few Republicans had denounced them.

Toomey did not directly touch on the racial implications of Trump’s comments, though other lawmakers (almost entirely Democrats) have. One exception, Rep. Will Hurd (R., Texas) called Trump’s tweets “racist” and “xenophobic” and described the president’s behavior as "unbecoming of the leader of the free world.”

The lawmakers Trump attacked are Rep. Alexandria Ocasio-Cortez of New York, who was born in the Bronx to parents of Puerto Rican descent; Rep. Rashida Tlaib of Michigan, whose parents are Palestinian immigrants and who was born in Detroit, and Rep. Ayanna Pressley of Massachusetts, who is black and was born in Cincinnati. The fourth, Rep. Ilhan Omar of Minnesota, is from Somalia and is now a U.S. citizen.

Trump would not back down Monday.

In a news conference, he said the Democrats he targeted “hate our country” and that “if you’re not happy here, you should leave.”

He said “it doesn’t concern me” that many see the tweets as racist, “because many people agree with me.”

Toomey has largely supported Trump’s agenda, particularly when it comes to lowering taxes, cutting regulations, and appointing conservative judges to the federal bench, but has criticized the president’s behavior at times, including over his moral equivocation after neo-Nazis and counter protesters clashed in Charlottesville, Va., in 2017.

Trump, who has previously derided the intelligence of another African American lawmaker, Rep. Maxine Waters (D., Calif.), has attacked black athletes who silently kneel during the national anthem. He once described Haiti and African nations as “shithole” countries.

He set off the latest racial furor Sunday on Twitter.

“So interesting to see “Progressive” Democrat congresswomen, who originally came from countries whose governments are a complete and total catastrophe, the worst, most corrupt and inept anywhere in the world (if they even have a functioning government at all), now loudly and viciously telling the people of the United States, the greatest and most powerful Nation on earth, how our government is to be run," he wrote. “Why don’t they go back and help fix the totally broken and crime infested places from which they came.”

Rep. Brendan Boyle (D., Pa.), of Philadelphia, who is white, noted on Twitter that he is also a young Democrat who comes from an immigrant family and criticizes Trump.

“Funny thing though, he never tells me to ‘go back where I come from.’ Hmm I wonder why,” Boyle tweeted.