Vandals defaced 20 stone plaques in the Jerusalem Forest commemorating the visits of foreign heads of state who had planted olive trees in a symbolic salute to peace, police said Tuesday morning.

The broken and toppled signs in the Grove of Nations were spray-painted with calls for the release of the three kidnapped Israeli teens. Additional graffiti in Hebrew reading “Kahane was right!” was found nearby, the latter being a reference to the late far-right rabbi and Knesset member Meir Kahane.

The site is “part of the initiative led by UNESCO and the Council of Europe to establish an Olive Tree Route around the entire Mediterranean basin expressing the common desire for peace and co-existence,” according to the JNF website.

Many foreign dignitaries have visited the site and made speeches advocating the need for peace after touring the adjacent Yad Vashem Holocaust museum and memorial.

The perpetrators were not found.

The vandalism follows the pattern of so-called “price tag” attacks, hate crimes usually carried out by Jewish ultra-nationalists in retaliation for government policies viewed as opposing the settler movement.

Mosques, churches, dovish Israeli groups and even Israeli military bases have been targeted by Israeli nationalist vandals in recent years. The acts have been condemned by Israeli leaders across the political spectrum.

On Wednesday police said vandals had scrawled nationalist slogans on a wall in the settlement of Ma’ale Adumim. The incident was under investigation.

Editors Note: This report has been edited to reflect that the site defaced was the Grove of Nations, which is in proximity to but not not affiliated with Yad Vashem.