(CNN) -- Scary, alarming, disheartening, unprecedented.
Those are just a few of the adjectives used to describe the recent widespread spate of bomb threats that have targeted Jewish Community Centers and schools in 33 states in the United States and two provinces in Canada.
President Donald Trump will use his speech to Congress on Tuesday night to address the issue, an administration official told CNN.
So far, none of the threats have been legitimate. But the lack of real destruction has not made them any less chaotic or anxiety-inducing.
"This is the first time in the 60-plus years of our organization we have had a bomb threat called in. And now we've had three bomb threats this year," said the CEO of a JCC in the Northeast who wished to remain anonymous for fear of copycats targeting his center. "It's alarming."
The alarm from the bomb threats, combined with the recent vandalism at Jewish cemeteries in St. Louis and in Philadelphia, have led some to see a pattern of rising anti-Semitism.
The series of bomb threats in recent weeks has disrupted day-to-day life, sparked fear in tight-knit communities, and raised difficult questions about what the federal government is doing to find out who's responsible.
"You ask me are the feds doing enough? And I'm really not sure," the anonymous CEO said.
The waves of threats
The incidents hit the larger public consciousness on January 9, when 15 different Jewish centers and schools received bomb threats. Since then, the threats have occurred in concentrated waves, with a series of threats on January 18, January 31, February 20 and February 27.
On Monday, another 31 threats were called in to 23 JCCs and schools, bringing the total number of bomb threats to 100.
Jewish community centers, or JCCs, function as hubs of communal activity for Jews and non-Jews alike. They host art and sports classes for children and adults, and help create connected communities of friends and families.
The threats have not been limited to the Northeast, or even just to the United States. They have targeted 81 different locations, spread across 33 states and two Canadian provinces, according to data from the JCC Association of North America.
On a basic level, the threats have interrupted regular life, forcing adults as well as children and infants to evacuate buildings on a moment's notice.
But on a deeper level, the threats have functioned like terrorism, shattering the idea of safety.
Joycie Porter of Syosset, New York, and her husband were at a JCC when a bomb threat came in. She said she and a group of kids from the nursery were ushered outside until it was safe to go back in.
"It's just very disheartening," Porter told CNN affiliate News 12 Long Island. "It's really a terrible time for us."
Rabbi Joan Glazer Farber of Tarrytown, New York, was in the middle of a workout when she was told to evacuate the building after a bomb threat.
"It's scary," she said. "I have a daughter who works at a JCC and she's gotten a call."
At JCCs across the country, parents have pulled their children from the centers out of fear. In a JCC in Orlando, Florida, which has received two threats, 50 students have been withdrawn. In Albany, New York, 12 families have removed children.
Dr. Jaime Huysman is the parent of a student at David Posnack JCC in Davie, Florida, which received a threat on Monday. Huysman told CNN affiliate WSVN that the threat was "particularly scary."
"My father's a Holocaust survivor, and I just called him up, and he's crying on the phone," Huysman said. "This shouldn't be happening in today's day and age."
Status of the investigation
The FBI said the bureau and the Justice Department's Civil Rights division are "investigating possible civil rights violations in connections with threats to Jewish Community Centers across the country."
But details on that investigation have been scarce, and it's difficult to know the extent of these threats. Are they all connected? Is this all the work of just one person, or more? Is there any rhyme or reason to which places are threatened?
Paul Goldenberg, national director of the Secure Community Network, which advises Jewish organizations on security, said the calls are "unprecedented" for their methodical approach and sophisticated use of voice-masking technology.
JTA News, a Jewish news service, posted audio of one of the bomb threats. In it, a warbled voice warns that a C-4 bomb has been placed in the JCC and that "a large number of Jews are going to be slaughtered."
"They could be 15 or 60 years old. These masking technologies are very effective," Goldenberg said.
Jewish leaders have called for a more robust response from the government to these threats, both in word and action.
"Anti-Semitism of this nature should not and must not be allowed to endure in our communities," the JCC Association of North America 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 JCC said.
White House response questioned
The White House in particular has been a target of criticism for its response -- or the lack of one.
Two weeks ago, Trump said a Jewish reporter had "lied" and told him to "sit down" after the reporter asked about the White House's plan to address anti-Semitism.
"No. 1, I am the least anti-Semitic person that you've ever seen in your entire life," Trump said. "No. 2, racism. The least racist person. In fact, we did very well relative to other people running as a Republican."
When the reporter spoke up again, Trump told him to be quiet. Later, when asked again about instances of anti-Semitism, the President said those were coming from his political opponents, not from Trump supporters.
Jonathan Greenblatt, CEO and director of the Anti-Defamation League, slammed Trump for not responding with a concrete plan to address the issue.
"In the face of danger, Trump dismisses critics, attacks journalists," Greenblatt said. "These are not answers to a simple question: What is he going to do about the surge in anti-Semitism?"
The White House has since worked to counter that criticism, releasing a statement last Monday denouncing the threats. Trump's daughter Ivanka, who practices Orthodox Judaism, tweeted about America's "principle of religious tolerance."
Still, at least publicly, there has been no statement about a broader investigative effort or special task force to address the threats.
Nonetheless, the threats have only emboldened some JCC attendees, like Felissa Allard of the Mid-Island Y JCC in Plainview.
"If anything, this direct attack on our community and those like it around the country are galvanizing us, bringing people together, and showing that we won't back down," Allard said.
CNN's Daniel Burke, Dominique Dodley, and Stephanie Gallman contributed to this story.
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