About a thousand people visited the grave of the biblical leader Joshua in the village of Kifl Haris near the settlement of Ariel on Wednesday night.
The visitors were shocked to discover swastikas and writings spray-painted on the wall at the grave complex.
This wasn't the first time offensive comments were written on the walls at the Samaria region site, and it was also set on fire several times in the past.
The Jewish worshipers visited the grave to mark the Seventh of Adar, the traditional day of death of Moses, whose own place of burial is unknown.
They prayed and studied Torah at the complex, and no other unusual incidents were recorded.
IDF soldiers and security forces from the Efraim Brigade secured the event.
Yossi Dagan, the head of the Samaria Regional Council, called on security forces to find and apprehend the vandals. "The grave of Joshua is a holy place with the highest level of historical significance. I call on security forces to capture the rioters. Only two weeks ago, the damned terrorist who murdered Itamar Ben-Gal escaped to this village," Dagan said.