Rep. Joaquin Castro of Texas is facing backlash after tweeting a list of 44 San Antonio natives who he said donated the highest individual amount allowed by federal law to President Trump in 2019. The tweet, which came from his Congressional campaign account, listed the donors' employers and even tagged some local prominent local business owners on the list.

Republicans slammed the San Antonio Democrat for sharing the names of donors, including House Minority Leader Kevin McCarthy of California, who wrote "Americans deserve better."

"Sad to see so many San Antonians as 2019 maximum donors to Donald Trump," Castro wrote. "Their contributions are fueling a campaign of hate that labels Hispanic immigrants as 'invaders.'"

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Some users supported the post, writing they would no longer frequent the establishments listed. The national Press Secretary for his twin brother Julián's 2020 presidential campaign, Sawyer Hackett, also tweeted in defense of the lawmaker. "This is a congressional campaign account tweeting a publicly available list of local max-out donors (many of whom are huge local business owners) to the president's campaign—a campaign that uses those funds to pay for ads calling immigrants 'an invasion,'" Hackett wrote.

However, many on the other side of the political aisle slammed the tweet.

Sad to see so many San Antonians as 2019 maximum donors to Donald Trump — the owner of ⁦@BillMillerBarBQ⁩, owner of the ⁦@HistoricPearl, realtor Phyllis Browning, etc⁩. Their contributions are fueling a campaign of hate that labels Hispanic immigrants as ‘invaders.’ pic.twitter.com/YT85IBF19u — Joaquin Castro (@Castro4Congress) August 6, 2019

"Elected officials are sent to D.C. to serve constituents, unfortunately Joaquin Castro made it clear he would prefer to publicly attack his constituents & neighbors b/c they don't share his ideology," wrote the official Twitter account for the Republican Party of Texas. "This is egregious and he should immediately delete this tweet and apologize."

"How low have Dems sunk?" asked Tim Murtaugh, Mr. Trump's reelection campaign's communications director. "Naming private citizens & their employers, targeting them for political views and exercising 1st Amendment rights. Should delete & apologize. Castro campaign should disavow."

"Targeting and harassing Americans because of their political beliefs is shameful and dangerous," McCarthy tweeted Tuesday. "What happened to "when they go low, we go high?" Or does that no longer matter when your brother is polling at 1%? Americans deserve better."

Castro doubled down on his comments late Tuesday, retweeting McCarthy's criticism."No one was targeted or harassed in my post," the lawmaker wrote in a thread. "Donald Trump has put a target on the back of millions. And you're too cowardly or agreeable to say anything about it. How about I stop mentioning Trump's public campaign donors and he stops using their money for ads that fuel hate?"

Targeting and harassing Americans because of their political beliefs is shameful and dangerous. What happened to “when they go low, we go high?” Or does that no longer matter when your brother is polling at 1%? Americans deserve better. https://t.co/PiFcifpxc1 — Kevin McCarthy (@kevinomccarthy) August 6, 2019

Castro's jab comes just days after a gunman opened fire at a Walmart in El Paso and killed 22 people and injured dozens of others. A racist manifesto that police believe was written by the accused El Paso shooter, posted online before the shooting, criticized a growing Hispanic population in Texas.

Many in El Paso have blamed Mr. Trump's anti-immigrant rhetoric for playing a role in inspiring the gunman. Democratic Rep. Veronica Escobar of El Paso said the president was not welcome in the city -- but the mayor said he considers welcoming the president's visit as his "formal duty."

Castro, the chair of the Congressional Hispanic Caucus, has regularly criticized Mr. Trump and his strict border policies.