On Sunday, a group gathered in Boulder, Colorado, to raise awareness for hostages held in Gaza was attacked, leaving 12 people injured.

The suspect, Mohammed Sabry Soliman, accused of throwing incendiary devices at them, allegedly planned the attack for a year, and told police he wanted to “kill all Zionist people,” according to court documents.

It was the latest in a string of attacks against Jewish people and institutions, ratcheting up anxiety among those in North America’s Jewish community who see these incidents as signs of growing antisemitism in the US.

The Boulder attack occurred just weeks after a suspect shot and killed a couple outside the Capitol Jewish Museum in Washington, DC. They were later identified as employees of the Israeli embassy who had been attending an event at the museum. In April, the official residence of Pennsylvania governor Josh Shapiro was set on fire, just hours after the Jewish lawmaker celebrated the first night of Passover.

“Jews are feeling the impact and are more afraid than they were two weeks ago, or that fears that existed in some communities a few weeks ago are more heightened,” said Adina Vogel Ayalon of J Street, a pro-Israel advocacy group that’s critical of the war and has called for a ceasefire in Gaza.

“These types of hate crimes are not distinguishing between where you fall on the political spectrum about the war” between Israel and Hamas, Ms Ayalon said. “And that is something very unsettling.”

Israel has faced sustained international criticism over its military actions in Gaza, which it undertook after Hamas attacked the country on 7 October 2023, killing about 1,200 people – mostly civilians – and taking 251 hostages.

Over 50,000 people have been killed in Gaza since the start of the war, according to the territory’s Hamas-run health ministry. The statistics do not distinguish between civilians and Hamas fighters, and the BBC and other international media organisations are blocked by Israel from entering Gaza to verify.

But a United Nations report that assessed Gazan deaths during a six-month period found nearly 70% of verified victims were women and children. Throughout the conflict, human rights experts have raised the alarm of widespread hunger, disease, and displacement within Gaza.

The war also has become a divisive political issue in the US. Pro-Palestinian protests across university campuses and in major cities have ignited greater debates over education and free speech. There are religious, generational, and partisan divides within the American Jewish community about support for Israel and the question of Palestinian statehood.

But the attacks in Boulder and Washington DC, struck a broader nerve because they crossed a “clear red line between legitimate free speech and political violence,” Ms Ayalon said.

Boulder’s attack has drawn condemnation outside the Jewish community.

“Acts of antisemitism have no place in our society,” the Muslim Public Affairs Council condemned the Boulder attack in a statement. “This violent assault is not only an attack on a specific community but a direct threat to the values of pluralism, dignity, and safety for all people of faith. As Muslims, our faith calls us to speak out against injustice and to uphold the sanctity of every human life.”

The group targeted in Boulder, Run For Their Lives, holds weekly meetings and marches across the country to call for the release of the remaining hostages taken to Gaza.

“The premise of the group is to peacefully raise awareness of the hostages. We’re apolitical, we’re not protesting anything,” said global coordinator Shira Weiss.

Many of the group’s members are Jewish and support Israel, but those are not requirements for participation.

“We get people from all walks of life – who vote Republican, Independent, Democrat, who support the Israeli government, or don’t support the Israeli government,” Ms Weiss said.

Safety has always been a top priority for group chapters, she said, but they “never thought such a violent attack would happen.”

Jewish communities and institutions across the US have long required security, but many bolstered their defences after a shooter espousing right-wing antisemitic conspiracy theories murdered 11 worshippers at a Pittsburgh, Pennsylvania synagogue in 2018. The following April, another shooter attacked a synagogue in Poway, California, killing one person and injuring three others.

Those conversations are again happening in the wake of the Boulder incident.

“The attacks, especially given the succession of attacks in a short period of time have made every Jewish American question their security, whether it’s their personal security or the security of Jewish institutions that they visit,” said Haliey Soifer, CEO of the Jewish Democratic Council of America.

“There’s a sense that what has occurred in DC and Boulder could have happened anywhere, could have happened to anyone.”

The Jewish Colorado organisation announced a fundraiser to support increased security for Boulder’s Jewish community, as well as financial and trauma support for victims of the attack. Its goal is $160,000.

Rabbi Dan Moskovitz of Temple Sholom in Vancouver, Canada frequently joins Run For Their Lives events and plans to continue advocating for the hostages in Gaza.

But he worries the Boulder attack would not be an isolated incident.

“It’s only going to inflame more radicalisation,” he said. “It’s only going to inspire more people to do those things.”