Updated

The U.S. is on high alert for possible attacks on American Jewish communities one year after Hamas staged the largest attack on Jews since the Holocaust. 

The FBI and Department of Homeland Security and FBI on Friday warned that the grim milestone since the Hamas terrorist attacks against Israel could motivate some people to engage in violence within the United States. 

In a public service announcement, federal authorities said the anniversary may motivate extremists and others to engage in hate crimes and provoke violence. 

"Over the past year, we have observed violent extremist activity and hate crimes in the United States linked to the conflict," the PSA states. "Jewish, Muslim, or Arab institutions—including synagogues, mosques/Islamic centers, and community centers—and large public gatherings, such as memorials, vigils, or other lawful demonstrations, present attractive targets for violent attacks or for hoax threats by a variety of threat actors, including violent extremists and hate crime perpetrators."

The PSA added that bad actors may "view" the Oct. 7 "anniversary as an opportunity to conduct an attack or other high-profile, illegal activity," and foreign terrorist organizations or "other violent extremists likely will continue to exploit narratives related to the conflict to call for lone attackers to conduct violence in the United States."

A flag of Israel with a yellow ribbon

A flag of Israel with a yellow ribbon added is seen near Frishman beach on October 03, 2024, in Tel Aviv, Israel. (Getty Images)

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Hamas killed 1,200 people and kidnapped hundreds of hostages during its brazen Oct. 7, 2023, terrorist attack on the Jewish state. The offensive sparked the ongoing war between Israel and the terror group. The war has since widened to include Hezbollah, an Iranian-proxy, which has launched rockets and missiles into northern Israel from its base in neighboring Lebanon for nearly a year in solidarity with Hamas. 

The Israelis responded by conducting airstrikes in Lebanon, taking out key Hezbollah leaders, as well as a ground operation launched this week. 

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Pro-Israel rally in New York

Pro-Israel counter protesters chant across a line of police officers towards a vigil organized by NYU students in support of Palestinians in Washington Square Park in New York City. (ALEX KENT/AFP via Getty Images)

The PSA noted that terror groups have consistently called for their supporters to provoke violence in the West, authorities said. Online messaging boards associated with terror groups could motivate those with antisemitic or Islamic views to act out violently, authorities said. 

Following Oct. 7, some parts of the U.S. have seen a spike in antisemitic incidents because of Israel's response to the attack on its citizens. The rise of antisemitism has been especially focused on college campuses where some Jewish students have been harassed, and, at times, assaulted.  

DHS' 2025 Homeland Threat Assessment (HTA), released last week, concluded that the "threat environment" in the United States over the next year is expected to "remain high."

"The Homeland Security Assessment provides an important overview of the dynamic and evolving threat landscape, illustrating just how varied and challenging the threats we confront are," Homeland Security Secretary Alejandro Mayorkas said in an Oct. 2 statement. "It is because of the remarkable DHS workforce, and our close collaboration with our federal, state, local, tribal, territorial, and private sector partners, that we are able to meet the challenges and keep the American people safe and secure."

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The FBI Crime Data Explorer revealed a total of 1,951 anti-Jewish hate crimes in 2023, a 55% increase from 1,257 incidents reported in 2022. Of these, 980 incidents occurred between January and September. In the final three months of the year, 971 incidents were reported, an increase of more than 300% over the 318 incidents tallied during the same period in 2022. 

Fox News Digital's Audrey Conklin and Beth Bailey contributed to this report.