The mayor of Deir Istiya, Ayyub Abu Hijlah, told Ma'an that settlers sneaked into the village before dawn prayers and set fire to the main door of the mosque, causing minor damages.
"Local residents, alerted by a worshiper who saw the fire while on his way to perform dawn prayer, scared the settlers away and put out the fire," he said.
PA official Ghassan Daghlas said that locals managed to extinguish the blaze before it spread to the interior of the mosque.
"Arabs out!" and "Best regards from Qusra," were sprayed on the mosque, according to Israeli news site Ynet.
Other graffiti reading: "The righteous shall rejoice when he seeth the vengeance: He shall wash his feet in the blood of the wicked" was also found.
Last Tuesday, villagers in the Qusra and Jalud area managed to apprehend a group of settlers who had attempted to attack them and their property, holding them for several hours in a house.
The settlers, who were from the illegal outpost of Esh Kodesh, were later transferred to Israeli security forces after the villagers called PA liaison officials.
Settler attacks against Palestinians and their property are routine and often happen in the presence of Israeli military forces.