Since the joint U.S.-Israeli operation against Iran began last Saturday, Jewish communities worldwide have seen an increase in threats and harassment — including a 95% rise in violent online posts targeting Jews, according to a new report from a leading American Jewish safety and security organization.   

A bulletin distributed by the Secure Community Network to law enforcement on Thursday reports that the ongoing strikes on Iran, which included the killing of former Supreme Leader Ayatollah Ali Khamenei on Saturday, have widespread foreign and domestic security implications.

Iranian ayatollahs Hossein Nouri Hamedani and Naser Makarem Shirazi on Sunday issued a fatwa calling on Muslims worldwide to take revenge for the killing of Khamenei. They told Muslim adherents to “aveng[e] the blood of the martyred leader of the revolution” and added that it “is obligatory for all Muslims.” Additionally, the Islamic Revolutionary Guard Corps issued a public proclamation in Farsi that “the enemy … will no longer have security anywhere in the world, even in their own homes.” 

The U.S. Department of Homeland Security responded in a confidential law enforcement report obtained by Jewish Insider that the fatwas, Iranian government rhetoric and online messaging heighten the threat of violent extremism in the U.S. 

SCN warned that the heightened risk of lone wolf attacks inspired by the strikes may have already begun to play out. Less than 24 hours after the killing of Khamenei, a gunman killed three people in a mass shooting at an outdoor beer hall in Austin, Texas. While authorities are still investigating a motive for the shooting, they noted that there were indicators on the suspect and in his vehicle that suggest a potential terrorist connection: During the attack, the suspect wore a hoodie with the words “Property of Allah” and a shirt with an Iranian flag design underneath. 

Since the airstrikes began in Iran, antisemitic online posts impacting the Jewish community — some of which use explicitly violent rhetoric — have nearly doubled, according to SCN, with 4,322 violent posts tracked in the past six days, compared to 2,211 in the week prior to the strikes. These posts include long-standing “Zionist Occupied Government” conspiracies about Israeli control over governments and influence in the U.S., as well as suggestions that the strikes were intended as blood sacrifices for the Jewish holiday of Purim. 

The Secure Community Network said it has not yet identified any specific threats to the Jewish community or U.S. homeland. In a list of precautionary recommendations, it urged law enforcement, security partners and Jewish institutions to remain vigilant, refrain from broadly advertising events and consider adding increased armed security. 

Retaliatory calls to harm American Jewish communities and facilities, in addition to general calls for “death to America,” have also proliferated online, including in tweets from Columbia University Apartheid Divest, a coalition of over 80 university student groups. 

New York City Mayor-elect Zohran Mamdani’s newly tapped director of appointments, Catherine Almonte Da Costa, resigned on Thursday afternoon after her history of antisemitic online posts — including complaining about “money hungry Jews” — was exposed.

“Catherine expressed her deep remorse over her past statements and tendered her resignation, and [Mamdani] accepted,” Dora Pekec, the mayor-elect’s transition team spokesperson, said in a statement to Jewish Insider.

Da Costa, who previously served as executive assistant to former Mayor Bill DeBlasio and was appointed by Mamdani on Wednesday, posted a series of antisemitic comments in 2011 and 2012, which were shared by the Anti-Defamation League. Da Costa’s account — and the posts, which had remained online — was deleted once the antisemitism watchdog published her posts on Thursday. 

“Money hungry Jews smh,” Da Costa posted on X in January 2011, according to screenshots. 

“Woo! Promoted to the upstairs office today! Working alongside these rich Jewish peeps,” she posted in June 2011.

In June 2012, Da Costa wrote that the “Far Rockaway train is the Jew train,” a reference to the neighborhood’s sizable Jewish population. 

Da Costa resigned on Thursday, saying that she “spoke with the Mayor-elect this afternoon, apologized, and expressed my deep regret for my past statements. These statements are not indicative of who I am. As the mother of Jewish children, I feel a profound sense of sadness and remorse at the harm these words have caused. As this has become a distraction from the work at hand, I have offered my resignation.”

Sara Forman, executive director of the New York Solidarity Network, praised “cutting ties” with Da Costa as” the right thing to do,” but added that “had she said ‘Zionist’ instead of ‘Jew’ the response from the incoming Mamdani administration and the outcome we just witnessed would likely have been quite different.”

“This is why we have been telling Mr. Mamdani all along that all anti-Jewish rhetoric, including anti-Zionist dog whistles, cannot just be ‘discouraged,’ it must be rejected and condemned outright,” Forman said in a statement.

The Anti-Defamation League of New York and New Jersey condemned the posts on X before Da Costa’s resignation, writing that they “echo classic antisemitic tropes and otherwise demean Jewish people.” 

“We appreciate Da Costa has relationships with members of the Jewish community, but her posts require immediate explanation — not just from Ms. Da Costa, but also from the Mayor-Elect,” the ADL said in a statement. 

The recently unearthed posts come as several of Mamdani’s transition appointees have drawn scrutiny from Jewish leaders, who remain skeptical of the mayor-elect, who takes office on Jan. 1, and his commitment to fighting antisemitism. 

Among the most controversial of his appointments is Tamika Mallory, a former Women’s March leader who stepped down from its board amid allegations of antisemitism, to a newly established community safety committee.