NABLUS (Ma'an) -- Jewish extremists cut down over 120 olive trees on private Palestinian land in Nablus on Tuesday, a Palestinian Authority official said.

The vandals were from the illegal settlement of Eli, Ghassan Daghlas, who monitors settler activity in the northern West Bank, told Ma'an.

Eyewitnesses said the settlers used chainsaws to destroy the trees, which belonged to 12 farmers in the village of Qaryut.

The attack comes on the official start date for the olive harvest in restricted areas of Nablus.

The set date was to enable farmers and local committees to better organize against potential settler attacks, as many restricted access areas lie adjacent to settlements.

Settler attacks often increase around the time of the olive harvest season as settlers target olive trees and agricultural land.

The Nablus district experienced the majority of settler violence in 2011.

On Sunday, a group of settlers attacked Palestinian farmers in the Ramallah town of Beitillu, burning dozens of olive trees, while settlers uprooted around 40 olive trees in the nearby Ramallah village of Ras Karkar.

On Friday, settlers destroyed 100 newly-planted olive saplings and at least 60 vine trees on private Palestinian land in Al-Khader village near Bethlehem.

The UN Office for the Coordination of Humanitarian affairs reported that over 2,500 olive trees were destroyed in September 2011, and 7,500 throughout 2011.

Settler attacks on Palestinian communities and their property are systematic and rarely prosecuted by Israeli authorities.

In an address to the UN General Assembly last month, President Mahmoud Abbas described to the world body "relentless waves of attacks" perpetrated by Israeli settlers in the occupied territories.

"During the past months, attacks by terrorist militias of Israeli settlers have become a daily reality, with at least 535 attacks perpetrated since the beginning of this year," Abbas said.

"The escalation of settler attacks should not surprise anyone, for it is the inherent byproduct of the continuation of occupation and a government policy that deliberately fosters the settlements and settlers and deems their satisfaction to be an absolute priority," he said.