In the middle of August, Josh Goldberg picked up his phone and saw a flurry of messages from worried friends claiming someone was impersonating him on Twitter.

The account was operating under a false name, Adam Greenblatt, and used a photo of Goldberg that was lifted from his YouTube page, where he uploads Jewish music he performs.

But this account wasn’t promoting Goldberg’s music — it was posting politically charged anti-Israel content and spreading hate speech against black people.

Goldberg, 28, is one of a handful of Jewish people who were targeted the week of Aug. 19 in a coordinated scheme created by internet trolls to instigate conflict within the Jewish community by creating fake accounts to spread extreme political views and hate speech, according to victims and posts about the campaign from 4chan obtained by NBC News.

“They wanted to masquerade as Jewish people and sow the seeds of divisions,” Goldberg said.

The anonymous troll who posted the original call-to-action on 4chan, a fringe online messaging board frequented by white supremacists, asked for people to create “a massive movement of fake Jewish profiles on Facebook, Twitter, etc.,” according to the 4chan post, which also contained an anti-Semitic trope. Soon after that message was posted, several accounts impersonating Orthodox Jews emerged on Twitter sharing anti-Semitic and anti-Israel content.

This 4chan campaign adds to growing concern that online extremism is translating into action online, and that these campaigns are also starting to inspire real-world violence.

“These kinds of things are usually the precursor to violence later,” Goldberg said.

His concerns come at a time where hate crimes against Jewish people have been growing worldwide. This year, Jewish people were targeted 110 times in hate crimes in New York, according to a June report from the city’s Police Department, up from 58 in 2018. And in France, a report by its National Human Rights Advisory Committee found that in 2018 anti-Semitic acts in the country had increased by more than 70 percent compared with 2017. Even Germany, which has stricter hate crimes laws, saw a 20 percent rise in anti-Semitic crimes, which includes hate speech, according to government data.

The troll campaign also provides yet another example of how online political discourse can be infiltrated and aggravated by outside groups, a strategy that was used by Russia-connected accounts in the run up to the 2016 election and that has been adopted by domestic trolls.

Avital Chizhik-Goldschmidt, an editor with The Forward, an online Jewish American publication based in New York, had just landed at Newark Liberty International Airport in New Jersey from France two weeks ago when she turned on her phone to discover that her husband had also been targeted by the same 4chan scheme.

The fake account was using a photo of her husband, a New York City rabbi, and featured a sign reading “Boycott Israel” behind her husband’s photo. After reporting it to Twitter, she found other accounts that seemed suspicious, too.

“These trolls were impersonating far left, social justice warriors who were promoting anti-Israel content,” Chizhik-Goldschmidt said. “It’s very disturbing how they got the language to seem real — like a real person was writing this.”

Chizhik-Goldschmidt said that she has seen plenty of online harassment as a Jewish journalist, but noted that this effort caused her concern because of how it could affect the Jewish community.

“These trolls had a goal of creating in-fighting in the Jewish community,” she said. “The Jewish community is already divided politically and they are anxious about their future, and these trolls really got it and tapped into the most vulnerable part of ourselves.”

Twitter confirmed it was aware of the 4chan campaign and was investigating related accounts and hashtags. Many of the accounts that were part of the campaign have been suspended.

“Based on our investigations, we have already permanently suspended several accounts. When we find accounts in violation of our policies, we take action according to our rules,” a Twitter spokesperson said.

Oren Segal, director of the Center on Extremism at the Anti-Defamation League, said the 4chan campaign isn’t the first time trolls from the message board had hatched a plan to target a minority group on other platforms. Other examples include 4chan trolls posing as gay men on Twitter to promote posts that falsely tied the LGBTQ community to pedophilia in January. In April 2018, 4chan users spread a fake Starbucks coupon offering free coffee to “people of color only.” In 2014, 4chan trolls were discovered to be falsely posing as black women who were calling for an end to Father’s Day to protest misogyny.

“The trolling we saw recently speaks to a larger effort of people trying to create divisions within groups like the Jewish community,” Segal said.

As social media companies focus on new technology and initiatives, Segal said she wants to see them address hate speech and content on their platforms, too.

“They all have a responsibility to address issues of hate,” he said.

Chizhik-Goldschmidt said she wants to stress to people that these campaigns have real-world impact.

“This tactic has power. It can become real and it does become real. The Pittsburgh shooting and El Paso shooting are good examples. These suspects said online what exactly they were going to do, and they did it,” she said. “We shouldn’t dismiss what happens online.”