A Russian Jewish organization called on authorities in Crimea to take action after vandals desecrated mass graves of Nazi victims outside the city of Simferopol, The Moscow Times reported on Friday.

“To desecrate the grave of those slain by the Nazis is sacrilegious and heinous to the utmost degree,” Alexander Boroda, head of the Federation of Russian Jewish Communities, said on Wednesday, according to the local Jewish News Agency.

Vandals dug four holes, each about 1.8 meters deep, at the site of the graves. Human bones and remains of clothing excavated from the graves were found scattered on the ground nearby, according to the report.

The desecrated graves were those of Jews, Roma and Soviet prisoners of war who were shot by Nazis in mass executions in late 1941, The Moscow Times said. The victims were stripped of jewelry, gold tooth fillings and valuable clothing before being shot, Boroda told the Jewish News Agency. Their bodies were then thrown in an anti-tank trench off the Simferopol-Feodosia highway.

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Boroda said violent antisemitic attacks have recently become more common in Russia.

“Now, more than 70 years later, there are monsters who follow along the beaten Nazi path and try to mock the dead,” he said. “The cynicism staggers the imagination. After all, those so-called people are obviously familiar with the history of the war because they easily find the sites of mass burials.”

A spokesperson for Crimea’s heritage preservation committee said the agency is working alongside Jewish leaders to persuade authorities to restore a police post once stationed at the site of the mass graves, the Russian news website Krym Inform reported.

“Otherwise there is nothing to stop the vandals; our employees cannot keep vigil there every night,” spokesperson Vyacheslav Zarubin said.

The attack comes as Russia prepares to celebrate 70 years since the Allied victory over Nazi Germany.

The incident is not the first time the mass graves outside Simferopol were desecrated. Vandals looted the graves in the 1980s and following a public outcry, they were found and tried publicly. Authorities then installed a concrete sarcophagus to protect the burial site, Krym Inform reported. The graves were vandalized again in April 2012 and three vandals were caught, tried and convicted.