The show went on.

Delayed 10 minutes by a phoned-in bomb threat, a performance by violinist Pinchas Zukerman eventually went ahead as planned Feb. 27 at the Oshman Family JCC in Palo Alto — an example of the prevailing spirit at local Jewish institutions in the face of what has become an alarming situation nationwide.

Since the start of the new year, 100 bomb threats have been called into JCCs and other institutions, a third of them on Feb. 27 alone. All were discovered to be false alarms, but no one in charge is relaxing.

Zack Bodner, CEO of the Palo Alto JCC, said such threats are a nuisance but are not going to stop JCCs and other Jewish institutions from fulfilling the daily role they play in the community.

“I would say we’re going to double down,” Bodner said the morning after the bomb threat, one of three received in the Bay Area. “This is an ‘I stand with the JCC’ kind of day. The community has really been coming out with full-fledged support. I am feeling very uplifted.”

Thank you for your warm words and help to ease the situation last night. We are ever grateful for your support. #IStandWithTheJCC pic.twitter.com/kKIDTevDiM

— Oshman Family JCC (@ofjcc) February 28, 2017

The threat in Palo Alto was one of 31 bomb threats received at Jewish institutions across the nation that day — including one that forced the evacuation of the downtown San Francisco office of the Anti-Defamation League.

Seth Brysk, regional director for the ADL, said a caller using a disguised voice warned that a bomb had been planted in the building “and that they were going to kill us.” The ADL offices, as well as neighboring buildings, were quickly evacuated, and several blocks of Market Street were shut down during the evening rush hour while police investigated.

“Somebody calls you and tells you they’re going to kill you and they planted a bomb in your building and they’re going to blow you up, it really frays the nerves,” Brysk said.

Based on the caller identification, the call to the ADL appeared to have come from within the ADL itself, except “defamation” was misspelled, a law enforcement source told J. The distorted voice was of a male caller, who said there was a bomb inside the building and many people would die as a result, according to the source. The voice sounded like it was repeating automatically, but then the caller responded to questions asked by the ADL staffer who answered the phone. (The source spoke on the condition of anonymity because they are not authorized to speak with the news media.)

Said Brysk: “This has been going on for weeks. We’d like to see action on the part of federal authorities and on the part of the president and his administration. He can repeatedly speak out and condemn these actions.”

There have been five such waves of threats in the past two months. Some 100 threats, none of which turned out to be real, have been called into Jewish facilities in 33 states since the beginning of 2017.

As in the previous hoaxes, JCC authorities and members said the threats were upsetting but would not lead them to cancel programs or otherwise change their plans.

“I am proud of our community’s response to these hateful anti-Semitic acts,” Daryl Messinger, a member of the OFJCC and chair of the board of trustees of the Union for Reform Judaism, said in a Facebook post. “We cannot permit our way of life to be threatened or our relationships to one another changed because of the hatred of a very few.”

The Osher Marin JCC in San Rafael also received a threat on Feb. 27, its second such call in less than six weeks. Iris Lax, the JCC’s director of marketing and strategic projects, said the facility was evacuated for about an hour, along with its afterschool program and the Brandeis Marin day school, which shares its campus.

By the next morning, she said, “It’s business as usual today. Everything opened at the normal time.”

Even though all of the recent threats have been hoaxes, there has been a history of violence and death at Jewish institutions during the last two decades.

In 1999, avowed white supremacist Buford Furrow fired 70 shots into the lobby of the North Valley JCC in Los Angeles, wounding five people, including three children. He then killed a mail carrier and fled the state before surrendering to police.

In 2006, six women were shot, one of them fatally, at the Seattle Jewish Federation. Naveed Haq was sentenced to life without parole plus 120 years for what the police classified as a hate crime. According to the Seattle Post-Intelligencer, in a 911 call following the shootings Haq complained that Muslims in the Middle East were “getting pushed around” by Israel.

And in 2014, neo-Nazi Frazier Miller shot two people to death at the JCC of Greater Kansas City and another at Village Shalom, a nearby Jewish retirement community. Miller was convicted of murder and sentenced to death.

After being assailed by critics for not speaking out against anti-Semitism, President Trump told Congress on Feb. 28 in his State of the Union address, “Recent threats targeting Jewish Community Centers and vandalism of Jewish cemeteries… remind us that while we may be a nation divided on policies, we are a country that stands united in condemning hate and evil in all its forms.”

On Feb. 22, more than 150 members of Congress signed a letter urging federal law enforcement officials to investigate the spate of recent bomb threats at JCCs and to “approach this issue with a sense of urgency.”

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The JCC Association of North America this week again urged federal officials to identify and capture those making the threats.

“Anti-Semitism of this nature should not and must not be allowed to endure in our communities,” David Posner, the organization’s director of strategic performance, said in a statement. “The Justice Department, Homeland Security, the FBI and the White House, alongside Congress and local officials, must speak out — and speak out forcefully — against this scourge of anti-Semitism impacting communities across the country.”

The Addison-Penzak JCC in Los Gatos said it will host a community meeting next week to discuss the recent bomb threats and the security procedures in place. An email from the APJCC about the March 8 meeting, which will include representatives from the FBI and the Los Gatos Police Department, stressed that such threats will not disrupt “our way of life” or undermine daily programs that serve everyone from preschoolers to gym patrons to seniors.

“Every day, we join our colleagues at JCCs throughout the country in celebrating Jewish life and opening our doors wide for the entire community to participate,” the APJCC email said. “The APJCC is a vibrant and pluralistic community with a common set of values, made up of Jews and non-Jews, those born in America and those who have immigrated, folks young and old, and people of all faiths and backgrounds.