The persistent threat of antisemitism was underscored Thursday after at least two people were killed in a U.K. synagogue attack. The violence unfolded as millions of Jews marked Yom Kippur, the holiest day in their faith, and as global efforts continued to free 46 Israeli hostages held by Hamas.

Details of the assailant, who attacked the Heaton Park Hebrew Congregation in England’s northeastern city of Manchester by ramming his car into pedestrians before stabbing at least one person, remain unknown.

British police shot and killed the suspect, and authorities declared the attack a terrorist incident.

“Attacks like the one today in the U.K. sadly are becoming normalized,” Jonathan Ruhe, Director of Foreign Policy at the Jewish Institute for National Security of America, told Fox News Digital.

People march with placards showing pictures of Israeli hostages as U.K. Jewish groups mark the first anniversary of the Oct. 7 Hamas attacks on Oct. 6, 2024, in Manchester, England. (Christopher Furlong/Getty Images)

Israeli Prime Minister Benjamin Netanyahu took to X to offer his condolences for the victims of the attack and said, “Israel grieves with the Jewish community in the UK after the barbaric terror attack in Manchester.

“As I warned at the UN: weakness in the face of terrorism only brings more terrorism. Only strength and unity can defeat it,” he added. 

While the motive behind Thursday’s attack remains unknown, Ruhe argued that the failure of European leaders to use “their diplomatic weight to support a viable post-Hamas future for Gazans” and instead “punish” Israel has contributed to the rise in antisemitic sentiment. 

The attack on the Manchester synagogue comes just two weeks after the U.K. and other European leaders agreed to recognize a Palestinian state after long refusing to do so. 

But anti-Semitism is also on the rise in the U.S., which Ruhe noted is possibly even more concerning given Europe’s history with combating the issue.

Jewish-targeted attacks in the U.K. rose 282% over the last decade, according to data collected by the CST. But in the U.S., antisemitic attacks jumped by 893% in the same 10-year period, according to the Anti-Defamation League, with some 9,354 incidents reported last year. 

“The rise of open and violent anti-Semitism in America is more recent than in much of Europe, but perhaps all the more worrying because of that,” Ruhe said. “Part of the solution is colleges shutting down far-left campus ‘protests’ that intend only to intimidate Jews and anyone who calls for policies short of ending Israel’s existence. 

“It’s been very telling that such ‘protesters’ use militarized language like ‘encampments’ to describe their campus presence and activities.” 

Former President Donald Trump walks on stage at a fighting antisemitism event with Miriam Adelson at Trump National Golf Club Bedminster Aug. 15, 2024, in Bedminster, N.J. (Adam Gray/Getty Images)

But Ruhe pointed out that anti-Semitism is an increasing concern across the political spectrum’s extremes, driving a narrative on both the far left and far right.

“There’s also a somewhat subtler normalization of antisemitism on the far right, for example, major influencers asking whether we need more context in talking about Adolf Hitler and Nazism,” Ruhe said. “There needs to be more serious and clear pushback from our political leaders on narratives like these.”