AMSTERDAM (JTA) — Nine headstones were knocked down at a Dutch Jewish cemetery.

The graves at the Jewish cemetery of Oud-Beijerland near Rotterdam, 45 miles south of Amsterdam, also showed signs of vandalism, police said, according to a report Wednesday in the Algemeen Dagblad daily.

Police have no information on the persons responsible for the damage and have asked witnesses to come forward. The vandalism occurred sometime after Tuesday, according to the report. The vandals also appeared to have brought down blunt objects on some of the damaged headstones.

”This is very nasty, and we are deeply saddened by it,” Ruvben Vis, the secretary of the Dutch Israelite Religious Community, or NIK, told the newspaper. “The final rest of the people buried there was disturbed,” he added.

Vis said the graves in Oud-Beijerland are 80 to 100 years old and that keeping them intact “is a moral responsibility that rests on our shoulders.”

The cemetery had a total of 68 graves, according to a report by the news site dichtbij.nl. Some of the headstones were desecrated with paint, according to that report.

In 2012, the Council of Europe passed a resolution that placed responsibility for Jewish cemeteries on governments. Jewish cemeteries “are part of the European cultural heritage” and are “probably more at risk than those of other faiths,” the resolution read.

Vandalism at Jewish cemeteries accounts for approximately 10 percent of the total anti-Semitic incidents recorded in Western Europe, according to Tel Aviv University’s Kantor Center for the Study of Contemporary European Jewry.