PHILADELPHIA — Dozens of volunteers from various faiths helped clean up a Jewish cemetery on Tuesday after scores of tombstones were toppled by vandals, as people from as far as Boston came to Philadelphia to rake leaves and pray for peace.

Police have not determined who was behind the vandalism at Mount Carmel Cemetery, which was reported over the weekend, or the motive. Various donors have come forward to offer a reward adding up to $50,000 for information leading to an arrest.

Republican President Donald Trump opened his address Tuesday night to a joint session of Congress with his strongest condemnation yet.

“Recent threats targeting Jewish community centers and vandalism of Jewish cemeteries,” Trump said, “remind us that, while we are a country that disagrees on policy, we stand united in condemning hate and evil in all of its very ugly forms.”