Jewish centres and schools across the US have received another wave of bomb threats as officials in Philadelphia try to repair and restore hundreds of vandalised headstones at a Jewish cemetery.
Community centres and day schools in at least a dozen states received threats, according to the JCC Association of North America. No bombs were found.
All 21 buildings – 13 community centres and eight 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.
David Posner, an official with the JCC Association of North America, said: “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.
“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 instil anxiety and fear in our communities.”
The FBI and the Justice Department’s Civil Rights Division are probing the threats.
Attorney general Jeff Sessions called the vandalism and bomb threats serious, unacceptable behaviour and said the department will “do what it can to assist in pushing back … and prosecuting anybody that we can prove to be a part of it”.
“We are a nation that is a diverse constituency, and we don’t need these kind of activities,” he said.
In Philadelphia, police investigated what they called an “abominable crime” after several hundred headstones were damaged over the weekend at Mount Carmel Cemetery, a Jewish cemetery dating to the late 1800s, said Steven Rosenberg, chief marketing officer of the Jewish Federation of Greater Philadelphia.
Police said the vandalism appeared to be targeted at the Jewish community, but 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 vandalism comes less than a week after a Jewish cemetery in suburban St Louis was targeted, with more than 150 headstones damaged.
The Philadelphia Building & Construction Trades Council, an umbrella group for more than 50 union locals that work in the construction industry, offered to repair the damage at Mount Carmel free of charge, calling it a “cowardly act of anti-Semitism that cannot be tolerated”.
A community clean-up organised by the Jewish Federation is to begin with as many as 50 volunteers per hour.
In Missouri, a Muslim crowdfunding effort to support the vandalised Jewish cemetery near St Louis had raised more than 136,000 dollars (£110,000) by Monday, with organisers announcing they would use some of the money for the Philadelphia cemetery.
About 200 people were evacuated from a Jewish Community Centre in York, Pennsylvania, after a caller told the front desk there was a bomb in the building, a spokeswoman said.
Jewish centres and schools in Alabama, Delaware, Florida, Indiana, Maryland, Michigan, New Jersey, New York, North Carolina, Rhode Island and Virginia were also threatened, according to the JCC Association of North America.
Since January, the group has tracked 90 incidents in 30 states and Canada.