World Jewish Congress President Ronald S. Lauder has condemned the desecration of the Mount Carmel Jewish Cemetery in Philadelphia as a “despicable and cowardly act of hatred” and urged citizens and local authorities across the United States to be vigilant against all signs of anti-Semitism.

In addition to the desecration, the second such act in one week, at least eight Jewish community centers and Jewish day schools across the country received bomb threats on Monday in the latest wave of threats to hit Jewish institutions, JTA reported.

The incidents are the fifth wave of such threats in less than two months.

Lauder said : “In recent weeks and months we have witnessed an unprecedented and inconceivable escalation of anti-Semitic acts in the United States, and unbelievably, they are continuing to occur. This is an attack not just on the Jewish community but on the very values of liberty and fraternity that America stands for. All Americans must treat these acts with utmost severity, and know that when hatred rears its ugly head, anyone can be a target.’’

“The desecration of the cemetery in Philadelphia and in St. Louis last week, are chillingly reminiscent of the pogroms the Jewish people suffered for centuries in Eastern Europe, and in the years of the Nazi rise to power,’’ he added.

‘’We must never be complacent in the face of such anti-Semitism, or any forms of hatred and bigotry, because even seemingly innocuous threats can all too quickly end in unspeakable horror,’’ Lauder stressed.

“As President Donald Trump said last week, the anti-Semitic threats against our Jewish communities are ‘a very sad reminder of the work that still must be done to root out hate and prejudice and evil.’’ We must all work together to stem this hatred once and for all,” he said.

Paul Goldenberg, director of the Secure Community Network, a group that advises Jewish institutions and organisations on security, said shortly after new reports of the bomb threats that his organization was working closely with the Department of Homeland Security and the FBI to identify the perpetrators and stop the threats.

Calling the continued threats “disturbing,” he said they are “impacting the lives of our communities out there.” He said Jewish institutions are “behaving in an exemplary manner” in the wake of the threats.

According to Malcolm Hoenlein, the head of the Conference of Presidents of Major American Jewish Organizations, ‘’anti-Semitism is taking on potentially “pandemic” dimensions globally, even in the US, and if left unchecked could grow into an immensely serious threat.

He has called on world leaders to convene a global summit to forcefully denounce the phenomenon.

“I think we’re seeing a pandemic in formation,” he told The Times of Israel.

“I don’t think it’s here. I think America’s situation is different from Europe. But the potential is there.”

“We saw anti-Semitism in Britain, we saw it in France, and now we see it’s spreading everywhere,” Hoenlein said. “Look at the numbers of incidents in Germany, Scandinavia and other parts of the world. And now we see in America swastikas being painted, other expressions such as phoned-in threats or aggression against kids on campuses. So it spreads. It’s not isolated to one geographic locale. It’s like a virus that spreads. And you have to declare it for what it is.”

“I don’t think now it’s a direct threat to Jewish existence or Jewish survival,” Hoenlein said about general trend of anti-Semitic acts committed recently in the US, including the desecration of Jewish cemeteries or bomb threats made to Jewish community centers. “I do think that this cancer, left unchecked, spreads and becomes more and more of a threat,” he added, citing as an example France where anti-Jewish sentiment “metastasized over a period of time.” It didn’t just happen,” he added, citing recent reports of attacks on Jews, and information from his own relatives who live in France telling him life has become “intolerable” there.

European governments have denounced such incidents and increased measures to protect Jews, Hoenlein said. “But we can’t deny the fact that anti-Semitism today is no longer something that has to be done under the cloak of darkness, with the fear of repercussions. Those restrictions are gone. And I think we have to reimpose it and there have to be standards set. That’s why I want government officials saying this is not acceptable, just like racism and bigotry in any other form is not acceptable.”