Image by Scott Olson/Getty Images White nationalist Matthew Heimbach fights with demonstrators at Michigan State University as he and other alt-right advocates try to attend a speech by white nationalist Richard Spencer on March 5, 2018 in East Lansing, Michigan.

NEW YORK (JTA) – The Anti-Defamation League found that 3,044 total acts of hate, extremism, anti-Semitism and terror were committed in the United States in 2018. 1,879 of these were anti-Semitic acts - including assault, vandalism and harassment.

Of these 1,879 acts of anti-Semitism, 249 (13 percent) were attributable to known extremist groups or individuals inspired by extremist ideology, according to the ADL’s classification system. In a call, Oren Segal, director of the ADL Center on Extremism, told the Jewish Telegraphic Agency that all 249 acts that they were able to attribute to extremists were carried out by white supremacists.

According to the ADL, “this category includes people associated with white supremacist groups or ideologies, including but not limited to neo-Nazis, the alt right, racist skinheads, Christian Identity, traditional white supremacists and white supremacist prison gangs.”

As for the remainder, Segal told JTA on the conference call that “most anti-Semitic incidents are carried out by average Joes and average Janes,” not by those affiliated with extremist groups.

The ADL also tracks other acts of domestic hate, extremism and terrorism. Right-wing individuals were responsible for 1,328 of these extremist acts – nearly 44 percent – and Islamist individuals were responsible for four, according to the organization’s own classification system.

Examining the ADL’s data going back to 2002, JTA found that 2,633 – approximately 34 percent – of the 7,686 reported non-anti-Semitic extremist incidents have been attributed to perpetrators with right-wing ideology, compared to 137 attributed to Islamists or those with a left-wing ideology.

“Neither side of the political spectrum is exempt from intolerance. The idea that this is a problem with only one side is wrong,” ADL CEO Jonathan Greenblatt told JTA during a conference call. However, he added that “white supremacy is a global terror threat.”

However, Greenblatt noted that many of the incidents the ADL reports come in from regional ADL offices, so researchers aren’t always certain of what other affiliations perpetrators might have.

“We don’t know if there might be more [extremist perpetrators] out there,” he said.

Correction: A previous version of this article stated that right-wing individuals were responsible for 71% of anti-Semitic extremist incidents. In fact, only 44% of total extremist incidents were attributed to right-wing individuals, and not all of those incidents were anti-Semitic. The article has also been updated to further distinguish anti-Semitic incidents from the total number of hate, extremism, and terror incidents tracked by the ADL.