An Anti-Defamation League task force tracking a spike in online harassment of journalists reported that self-identified supporters of Donald Trump are responsible for the lion’s share of anti-Semitic tweets aimed at reporters and broadcasters.

In the latest such incident, a Jewish journalist at the political news website Politico was targeted with anti-Semitic messages. An altered image of Hadas Gold, the editor of Politico’s On the Media blog, was posted Oct. 18 on Twitter, showing a bloody bullet hole in her forehead and a yellow star similar to those worn by Jews in Nazi Germany pinned to her chest. She also received emails with threatening anti-Semitic messages.

“Don’t mess with our boy Trump or you will be first in line for the camp,” read a message on top of the photo. “Aliyah or line up by the wall, your choice.”

Fellow Jewish Politico writer Julie Ioffe retweeted the attack on Gold, and in response a Trump supporter tweeted an image of Ioffe’s face inside an oven, a reference to the Nazi death camps. Ioffe had been earlier targeted with anti-Semitic attacks on social media after she penned a critical profile of Trump’s wife, Melania, in May.

While emphasizing that the study does not imply that the Republican presidential nominee’s campaign supports or endorses the Twitter activity, the ADL task force noted that the terms that appear most frequently in the bios of the 1,600 Twitter users who account for more than two-thirds of the anti-Semitic tweets aimed at journalists are “Trump,” “nationalist,” “conservative” and “white.”

The study saw a significant uptick in anti-Semitic tweets from January to July as coverage of the presidential campaign intensified.

The report identified 2.6 million anti-Semitic tweets between August 2015 and July 2016 with an estimated reach of 10 billion readers, which the task force believes “contributed to reinforcing and normalizing anti-Semitic language — particularly racial slurs and anti-Israel statements — on a massive scale.”

Of those 2.6 million, ADL focused its analysis on tweets directed at 50,000 journalists in the United States, finding 19,253 anti-Semitic tweets directed at them. A disproportionate number were directed at a small number of journalists. The top 10 most targeted journalists, who received 83 percent of the overtly anti-Semitic tweets, were all Jewish, including columnist Ben Shapiro of DailyWire.com, Tablet’s Yair Rosenberg, the Atlantic’s Jeffrey Goldberg, the New York Times’ Jonathan Weisman, CNN’s Sally Kohn and Bethany Mandel of the New York Post.

The ADL said it will provide a list of offending accounts to Twitter; the social media platform previously deactivated 21 percent of the accounts responsible for the tweets aimed at journalists.

“The spike in hate we’ve seen online this election cycle is extremely troubling and unlike anything we have seen in modern politics,” Jonathan Greenblatt, the ADL’s CEO, said in a statement. “A half-century ago, the KKK burned crosses. Today, extremists are burning up Twitter. We are concerned about the impact of this hate on the ability of journalists to do their job and on free speech, which is why we established this task force.”

While much of the online harassment of journalists was sent anonymously, the ADL noted that they originated with a number of overlapping “communities” associated with the alt-right and white nationalist movements. It also identified two neo-Nazis responsible for some of the attacks: Andrew Anglin, founder of the white supremacist website the Daily Stormer, and Lee Rogers of Infostormer (formerly the Daily Slave).

“While both are banned from Twitter, they have encouraged their followers to tweet anti-Semitic language and memes at Jewish journalists,” according to the task force.

Meanwhile, a top Reform movement rabbi has said it “defies belief” that Trump is unaware of anti-Semitic associations in his campaign rhetoric.

Rabbi Jonah Pesner, who directs the Reform movement’s Religious Action Center, released his statement Oct. 14, a day after Trump delivered a speech in West Palm Beach, Florida, alleging that Hillary Clinton was part of an international conspiracy aimed at rigging the election.

Trump did not mention Jews during the speech but “such imagery has a long and vile history among those who perpetuate anti-Semitic tropes,” Pesner said. He also noted that Trump and his surrogates have attacked advisers and donors to Clinton, often naming those who are Jewish.

“During the second presidential debate [on Oct. 9], Mr. Trump appeared to take special pains to mention the names of Jewish acquaintances, colleagues and advisers to Secretary Clinton,” Pesner said.

“It defies belief to assume that Mr. Trump is unaware of the anti-Semitic associations of the messages he is espousing — nor can he be unaware that such messages are being celebrated by neo-Nazis and alt-right organizations,” Pesner said. “Mr. Trump must act responsibly by ceasing to disseminate false, historically anti-Semitic associations. He must also unequivocally repudiate the support of anti-Semites who have embraced his candidacy.”