Jewish centers and schools across the nation coped with another wave of bomb threats Monday as officials in Philadelphia began raising money to repair and restore hundreds of vandalized headstones at a Jewish cemetery.



Jewish Community Centers and day schools in at least a dozen states received threats, according to the JCC Association of North America. No bombs were found. All 20 buildings -- 13 community centers and seven schools -- were cleared by Monday afternoon and had resumed normal operations, the association said.



It was the fifth round of bomb threats against Jewish institutions since January, prompting outrage and exasperation among Jewish leaders as well as calls for an aggressive federal response to put a stop to it.



"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," said David Posner, an official with JCC Association of North America.

"Members of our community must see swift and concerted action from federal officials to identify and capture the perpetrator or perpetrators who are trying to instill anxiety and fear in our communities."



The FBI and the Justice Department's Civil Rights Division are probing the threats.



In Philadelphia, police investigated what they called an "abominable crime" after several hundred headstones were toppled during the weekend at Mount Carmel Cemetery, a Jewish cemetery dating to the late 1800s.



Police said the vandalism appeared to be targeted at the Jewish community, though they cautioned they had not confirmed the motive. Philadelphia Mayor Jim Kenney said authorities were doing everything possible to find those "who desecrated this final resting place."



The damage comes less than a week after a Jewish cemetery in suburban St. Louis reported more than 150 headstones vandalized, many of them tipped over.



"I'm hoping it was maybe just some drunk kids," said Aaron Mallin, who discovered the damage at the Philadelphia cemetery during a visit to his father's grave. "But the fact that there's so many, it leads one to think it could have been targeted," he told WPVI-TV.



Well-intentioned volunteers rushed to the cemetery after the damage was discovered Sunday to begin putting the headstones back up, complicating efforts to tally the damage and perhaps investigate the crime, said Steven Rosenberg, chief marketing officer of the Jewish Federation of Greater Philadelphia.



A day later, Jewish Community Centers in nearby Cherry Hill, N.J., and Wilmington, Del., and a day school in the Philadelphia suburbs were among those getting bomb threats that Rosenberg called a "complete nuisance."



"There's plenty of people who are scared," said Rosenberg, who denounced the hoaxsters as "an embarrassment to civilized society."



Some 200 people were evacuated from a Jewish Community Center in York, Pa., after a caller told the front desk there was a bomb in the building, said Melissa Plotkin, the York JCC's director of community engagement and diversity. Police entered the building and cleared it, she said.



Pennsylvania Gov. Tom Wolf, who has long ties to the York center, having served on its board, called the bomb threats and cemetery vandalism reprehensible.



"These acts are cowardly and disturbing," Wolf told reporters in a conference call Monday. "We must find those responsible and hold them accountable for these hate crimes."



Jewish centers and schools in Alabama, Delaware, Florida, Indiana, Maryland, Michigan, New York, North Carolina, Rhode Island and Virginia also were threatened, according to the JCC Association of North America.



Since January, the group has tracked a total of 89 incidents in 30 states and Canada.



Paul Goldenberg, director of the Secure Community Network, a nonprofit founded by several national Jewish groups to bolster security in the Jewish community, said Jewish Community Centers and other Jewish institutions have extensive security protocols in place.



After dealing with Monday's threats, he said, the "Jewish community is back in business."