The phone rang Monday morning at the Levite Jewish Community Center outside Birmingham, Ala., and a receptionist answered it. There was a bomb in the building, the caller said, before hanging up.
It was the second bomb threat in five weeks against the center, which is located in the town of Mountain Brook and includes an athletic complex and day-care center.
"Unfortunately, we're now well-rehearsed at this," said Betzy Lynch, the center's director. Though most of its 3,000 weekly visitors are not Jewish, she had no doubt that the motive of the calls was anti-Semitism.
The call Monday appeared to be part of a coordinated attack on Jewish community centers across the country. That morning a total of 11 centers — from Albuquerque to Buffalo, N.Y. — received bomb threats. It was the fourth time this year that Jewish community centers were targeted.
In just over six weeks, 53 centers in 26 states and one Canadian province have received 68 bomb threats. Though all have been hoaxes, the threats have spread fear among American Jews in a way unseen in recent years.
Adding to the alarm, nearly 200 gravestones at a historic Jewish cemetery outside St. Louis were toppled over the weekend in what law enforcement is investigating as a possible anti-Semitic hate crime.
On Tuesday, after weeks of deflections from the White House over requests to publicly address concerns from Jewish American leaders, President Trump issued a strong denunciation of anti-Semitism.
"The anti-Semitic threats targeting our Jewish community and community centers are horrible, and are painful, and a very sad reminder of the work that still must be done to root out hate and prejudice and evil," Trump said while speaking to reporters at the National Museum of African American History and Culture in Washington.
His statement followed a tweet Monday from his eldest daughter about the bomb threats.
"America is a nation built on the principle of religious tolerance. We must protect our houses of worship & religious centers. #JCC," Ivanka Trump wrote, using a hashtag for Jewish Community Center. A convert to Judaism, she is married to Jared Kushner, a senior advisor to her father.
The president's remarks assuaged some Jewish leaders who have been growing anxious over anti-Semitism and had directed part of their anger at Trump.
During his campaign, he retweeted white supremacists and anti-Semites, earning him support from the Ku Klux Klan and other hate groups. One of the president's tweets attacking Hillary Clinton used imagery that Jewish leaders and others charged was anti-Semitic.
More recently, the Trump administration intentionally did not mention Jews in a statement it released for Holocaust Remembrance Day — then drew more criticism from Jewish leaders for defending that decision.
When an Orthodox Jewish reporter at a news conference last week began to ask Trump about anti-Semitism, the president cut him off and told him to "sit down" before saying, "I am the least anti-Semitic person."
Jonathan Greenblatt, chief executive of the Anti-Defamation League, had criticized the president for not speaking out more forcefully against anti-Semitism.
On Tuesday, after Trump's latest remarks, he tweeted: "Glad @POTUS stated #antisemitism is horrible. Now need @whitehouse to share plans on how to 'stop' it. ADL ready to help."
The wave of threats has spurred synagogues and Jewish community centers and schools across the country to step up security. On Monday, the ADL sent a 12-part checklist to its branches instructing them to review guidance on how to handle bomb threats, unusual packages and suspicious guests.
"While each of these threats must be taken seriously, and investigated by law enforcement, bomb threats are usually used as scare tactics in order to disrupt an institution's operations, and cause fear and panic," the letter said.
David Simon, executive director of the Jewish Community Center of Greater Albuquerque, which has received bomb threats twice in the last month, blamed the presidential campaign.
The election "opened a Pandora's box of hate speech," he said. "People who harbor these radical, hateful views have felt emboldened and empowered to some extent. That's un-American. There's no question that there's some things happening domestically that are different now than they were four months ago."
"Am I scared? Not really," he said. "I don't think our JCC is going to be bowed by these kinds of threats. If anything, I think it's going to make us stronger."
Jews have regularly been near the top of the FBI's annual list of groups most targeted by hate crimes.
Of 1,244 crimes motivated by religious bias in 2015 — the most recent statistics available — 53% were directed at Jews. Hate crimes against them rose 9% over the previous year.
In the weeks after the November election, the Southern Poverty Law Center in Montgomery, Ala., used media reports and its own reporting system to catalog more than 1,000 incidents of violence, threats or vandalism against minority groups, including Jews. Many of the attacks were thought to be motivated by divisions stirred during the presidential campaign.
But some experts said recent alarm could give a false impression of the bigger picture for Jewish Americans.
"These threats and attacks come amid a backdrop of increasing acceptance of Jews" since World War II, said Brian Levin, a professor at Cal State San Bernardino who tracks hate crimes.
Though Jews are among the most commonly targeted minorities for hate crimes, they also rank as one of the most liked religious groups in the country, he said.
A survey released last week by the Pew Research Center asked respondents to rate their feelings on religious communities and found Jews to be the highest ranked, faring better than they did in a similar survey three years ago. Overall, positive feelings about nearly all religious groups, including Muslims, increased.
That's the kind of sentiment Brian Greene, executive director of the Westside Jewish Community Center in Los Angeles, said he kept in mind amid the recent threats and violence.
"We're a JCC that serves Jews and non-Jews, and everybody in the neighborhood, and they're still coming," he said.
The center has not been targeted, but the staff has met with police and reviewed security procedures just in case. Greene said there had been no drop-off in attendance among the nearly 10,000 visitors that make it to the facility each week.
"There's no reason to overreact," he said. "But we are aware of what's going on and we are making sure that we're ready should such a call come here."