The Jewish Community Center Association wants a meeting with the Justice Department to discuss a series of bomb threats against JCCs across the country. Above, a police officer blocks an entrance as officials respond to a bomb threat at the Jewish Community Center in Louisville, Kentucky, March 8, 2017. Bryan Woolston/Reuters

A group of Jewish community centers Wednesday asked the Justice Department to step up its investigation of anti-Semitic threats against Jewish institutions, citing growing “anxiety and fear in communities across the country.”

The Jewish Community Center Association sent a letter to Attorney General Jeff Sessions, expressing frustration with the pace of the investigation and seeking a meeting “as soon as possible.”

More than 100 threats have been made against Jewish community centers in 30 states since the beginning of the year. So far all of the threats have been hoaxes.

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“President [Donald] Trump forcefully condemned the situation at the outset of a speech to Congress, [the Department of Homeland Security] has promised heightened support to JCCs through its protective advisers, and our leadership had the chance to meet with FBI Director [James] Comey,” the letter reads.

“Still we are frustrated with the progress in resolving this situation. We insist that all relevant federal agencies, including your own, apply all the resources available to identify and bring the perpetrator or perpetrators, who are trying to instill anxiety and fear in communities across the country, to justice.”

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The letter notes JCCs serve their entire communities, not just its Jewish members, providing a safe environment for children, teens, adults and seniors.

“More than 2 million people pass through our doors each year to take part in our programs and the JCC Movement has been a part of North America’s landscape for the last century,” the letter says.

It continues: “The potential ripple effect of these threats locally and nationally cannot be understated.”

In addition to the threats against JCCs, there have been threats against Jewish day schools and vandalism at synagogues and cemeteries.

At least 12 Jewish schools and community centers were threatened Tuesday in Chicago, Washington, New York, Atlanta, Boston; Whitefish Bay, Wisconsin; Davie, Florida; Framingham, Massachusetts, Rockville, Maryland; Rochester and Syracuse, New York, and Portland Oregon.

Four Jewish cemeteries were vandalized in St. Louis, Philadelphia, and Rochester and Brooklyn, New York, last month, and a garbage can was thrown through the window of a Chicago synagogue Feb. 4.

The Anti-Defamation League reported 941 anti-Semitic incidents in the United States in 2015, up 3 percent from 2014’s levels.

“We are disturbed that violent anti-Semitic incidents are rising,” ADL CEO Jonathan A. Greenblatt said. “And we know that for every incident reported, there’s likely another that goes unreported. So even as the total incidents have remained statistically steady from year to year, the trend toward anti-Semitic violence is very concerning.”

Anti-Jewish rhetoric has increased in the last year on the internet during the presidential campaign, spurred in part by Breitbart News, which gave alt-right groups a more mainstream platform for their vitriol.