A group of “online trolls” made fake bomb threats and swatting calls against more than two-dozen synagogues across the US in what the Anti-Defamation League called a sickening display of antisemitism Sunday.

The group targeted at least 26 synagogues and two ADL offices across 12 states over the last four weekends, according to the organization.

The ADL is working with law enforcement and other community members to prevent the “ongoing disruption to Jewish prayer services, as well as additional targets, by a group of online trolls who swat and call in fake bomb threats,” Jonathan Greenblatt, CEO and national director of the ADL, said in a statement Sunday.

The suspects appear to go after synagogues that livestream their services, the ADL said.  

“These trolls, who employ highly antisemitic language during their calls, have targeted over two dozen synagogues and two ADL offices,” Greenblatt said. “They also appear to have expanded their targets, including several African-American churches and a news organization.”

“The ADL Center on Extremism is working closely with law enforcement to identify the individuals responsible for these concerning and potentially dangerous activities,” he added.

In one instance, a synagogue in Fremont, California was forced to evacuate worshippers Friday after a possible bomb threat was made, police said.

The disturbing call came in to Beth Torah Jewish Temple around 8 p.m., KTVU reported. Responding cops evacuated members inside, and searched the building and surrounding area, but didn’t find any suspicious devices or people, police said.

Synagogue officials reportedly told police they heard about similar hoaxes that happened at other synagogues in the state.

Fullerton synagogue members were forced to flee during Sabbath services Saturday when a bomb threat was received around midday, police told City News Service, according to NBC Los Angeles.

The LAPD called Fullerton police to let them know they received a call that a bomb was about to go off at Temple Beth Tikvah in 20 minutes.

About 30 people at the synagogue evacuated as authorities searched the property. No explosive device was found, police said.

“Sadly, this is something that many temples, many Jewish houses of worship… have to live with,” Rabbi Mati Kirschenbaum told the station.

The ADL’s statement also comes a day after a synagogue on the Upper East Side was targeted by an unknown individual who scrawled antisemitic graffiti on the message board outside.

The suspect, a man who appeared to be around 25, took a marker out after he walked up to the Congregation Kehilath Jeshurun Synagogue around 7 p.m. on Saturday and carried out the hateful act, police said.