In a letter to employees that BuzzFeed posted online, website founder and CEO Jonah Peretti described the move to pull out of the RNC’s ad-buy, which Politico has reported was worth $1.3 million, as “a business decision” spurred by the opinion that Trump’s campaign “is directly opposed to the freedoms of our employees in the United States and around the world.”

According to BuzzFeed, which published Peretti’s email to employees in full, the website signed its ad deal with the RNC in April, with Peretti noting that BuzzFeed typically takes ad money from candidates on both sides of the aisle. Since April, though, Donald Trump has more or less wrapped up the Republican nomination for president. Peretti wrote that BuzzFeed informed the RNC on Monday morning that the site is not willing to post ads supporting Trump’s presidential bid, so the website terminated its agreement with the organization.

The email from Peretti explained:

“The Trump campaign is directly opposed to the freedoms of our employees in the United States and around the world and in some cases, such as his proposed ban on international travel for Muslims, would make it impossible for our employees to do their jobs…..We certainly don’t like to turn away revenue that funds all the important work we do across the company. However, in some cases we must make business exceptions: we don’t run cigarette ads because they are hazardous to our health, and we won’t accept Trump ads for the exact same reason.”

BuzzFeed’s news staff has regularly butted heads with Trump and his campaign, with the site’s reporters having reportedly been denied press credentials at Trump campaign events. And, Trump campaign manager Corey Lewandowski at one point took issue with a BuzzFeed report alleging that he made unwanted sexual advances toward female journalists.

Peretti reiterated that the move was not an editorial decision, noting the “wall between our business and editorial operations.” He stressed that the decision “will have no influence on our continuing coverage of the campaign.” Still, it’s hard to see this public announcement as anything but a slap at Trump.

Generally, the business side of news organizations try to stay far away from such disputes. Peretti’s letter is yet another sign of just how extraordinary this political season is—as well as the strained relationship between Trump and the media.

The RNC responded to BuzzFeed’s public announcement with a shrug, telling the press on Monday that the group reserved ad space with several online platforms, but “never intended to use BuzzFeed.” In a statement to multiple publications, RNC communications director Sean Spicer also said it is “ironic that they have not ruled out taking money from a candidate currently under investigation by the FBI,” in a reference to Democratic frontrunner Hillary Clinton. When reached for comment by Fortune, a spokeswoman for Donald Trump’s campaign said the candidate had no comment and pointed to the RNC’s statement.

It is worth noting that BuzzFeed’s advertising model involves the website charging ad clients for advertising content that BuzzFeed staff creates itself, rather than accepting pre-made content and simply posting it on the website. In other words, by terminating the RNC deal, BuzzFeed is effectively saving its own employees from having to create content, called native ads, that promotes a candidate whose views the company says it opposes.

BuzzFeed is certainly not the first publication to publicly take a stance in opposition to Trump’s campaign, as The Huffington Post initially stated it would only cover Trump’s campaign under its entertainment section and later attached an editor’s note to Trump stories calling the candidate “a serial liar, rampant xenophobe, racist, misogynist and birther.” Peretti is a co-founder of The Huffington Post.