Damaged graves and racist graffiti have been found in the Palestinian village of Awarta in the northern West Bank after a Jewish group visited the area.
Palestinians said they had seen Jewish pilgrims, escorted by Israeli soldiers, in the area, which is also a Jewish burial site.
The Israeli military said it viewed the incident very seriously and was opening a military police investigation.
It comes a month after an arson attack on a mosque in the same area.
At least two tombstones were damaged in the cemetery outside the village, and food and rubbish were left on graves.
In the village, offensive slogans about Arabs were found scrawled in Hebrew, English and Russian.