A small cohort of self-identified Donald Trump supporters, white nationalists, and conservatives are behind this election cycle’s barrage of anti-Semitic Twitter attacks on journalists, according to a new Anti-Defamation League report out Wednesday.

Using a broad set of keywords to identify anti-Semitic language, an ADL task force found that only 1,600 Twitter accounts were responsible for directing 19,253 anti-Semitic tweets at some 800 U.S. journalists on the social media site between August 2015 and July 2016.

The most common words in the bios for those accounts were “Trump,” “nationalist,” “conservative” and “white.”

“I can’t say that there’s causation but there is certainly a very clear statistical correlation,” ADL President Jonathan Greenblatt told TPM in a phone interview, adding that the task force didn’t find any statistically significant evidence of Hillary Clinton supporters spreading anti-Semitic messages.

The ADL tapped seven journalists including Columbia University journalism school dean Steve Coll, Atlantic contributing editor Leon Wieseltier, and New York Post writer Bethany Mandel in April to form the task force and look into the rising tide of anti-Jewish invective online.

As a non-profit, the ADL, which works to combat anti-Semitism, does not support any political candidate or party. While the task force’s report repeatedly emphasizes that Trump has not personally encouraged or condoned such hate speech, it contains striking findings about how his campaign has animated anti-Semites.

Their research found the volume of anti-Semitic tweets directed at journalists soared from February onward, as election coverage intensified. They also spiked significantly during certain moments in the news cycle, including Feb. 29, during coverage of Trump’s initial refusal to condemn former Ku Klux Klan leader David Duke; March 13, when Trump blamed Sen. Bernie Sanders (I-VT) for violence at one of his campaign rallies; and May 17, when Melania Trump claimed that Julia Ioffe, a Politico contributor who wrote a profile of her, “provoked” the anti-Semitic attacks she received on social media.

The task force concluded that this surge points to an “intentional and coordinated” attack against Jewish journalists in order to intimidate them. While many of the users appear to be anonymous trolls, they take marching orders from white supremacist leaders who are themselves banned from Twitter. Daily Stormer founder Andrew Anglin and Infostormer founder Lee Rogers told their followers to go after Ioffe for her Melania Trump profile, and her account was soon flooded with messages calling her a “filthy Russian kike” and threatening to burn her in an oven.

Indeed, out of the 19,253 anti-Semitic tweets directed at journalists during this election year, the report found 83 percent of the attacks were directed at just 10 Jewish journalists: Ben Shapiro, Yair Rosenberg, Jeffrey Goldberg, Sally Kohn, Jonathan Weisman, Jonah Goldberg, Jake Tapper, Wolf Blitzer, Dana Schwartz and Bethany Mandel.

According to the ADL’s Greenblatt, though, the anti-Semitic abuse journalists received was often unrelated to the election itself.

“Their message is ‘Jews control the media, Jews control global finance, Jews did 9/11.’ So they’re exploiting the election to push their prejudice,” Greenblatt said.

“50 years ago they did this behind white sheets, today they do it behind their keyboards and their smart phone screens,” he added. “The medium is different; the message is the same.”

The net effect is taking a toll. According to Greenblatt, the report was inspired by the stories of journalists who told the ADL that they were avoiding pursuing certain stories because they feared harassment or even were considering leaving their profession after Election Day.

The report, he said, confirmed the group’s suspicion both that this hate speech is making some journalists feel unable to do their jobs and that anti-Semites are spreading their message to an even larger audience using online platforms. While over 19,000 anti-Semitic tweets were directed at reporters specifically since last August, an astounding 2.6 million anti-Semitic messages were sent in that time period overall, with over 10 billion impressions.

“That’s an extraordinary degree of exposure that the extremists had not had,” Greenblatt said. “Because we as a society I think had relegated that kind of speech to the margins where it belongs.”

The task force notes in the report that it “cannot and do not assign blame to Mr. Trump for these ugly tweets,” because those who share them are “solely responsible for their messages.”

Yet Trump and his advisors have on multiple occasions retweeted images from unabashed anti-Semitic or white nationalist Twitter accounts. The real estate mogul came under fire earlier this year for sharing a meme calling Clinton corrupt that featured the candidate’s face on top of a pile of cash and next to six-pointed star that resembled the Star of David.

Just last week, Trump gave a speech decrying the elite global conspiracy of bankers and media interests bent on defeating his campaign and electing the Democratic nominee Hillary Clinton.

Greenblatt noted that the ADL has “spoken out when memes from the alt-right have found their way into his Twitter feed” and that he shared a message on Twitter last week calling for Trump’s team to avoid “rhetoric tropes that historically have been used ag. Jews & still spur #antisemitism.”

The ADL, which already works with Twitter and other tech companies to address hate speech, will release a second part of the report after Election Day laying out recommendations for legislators and social media platforms. For now, Greenblatt said, the press should continue to report on anti-Semitic and other bias attacks.

“The best disinfectant is sunlight,” he said. “If we don’t give this attention, it’s only going to get worse.”

Read the full report below: