Residents of the village of Al-Maghir, east of Ramallah, reported that a mosque was set on fire early Wednesday, around 3:30 a.m.
The residents said that the lower floor of the mosque was damaged. They said that they also discovered anti-Arab graffiti on the walls of the mosque, which lies in the western part of the village.
The villagers claimed that "settlers" were behind the arson. A Palestinian Authority security official in the West Bank also blamed "extremist settlers" for the arson.
Israel Radio reported that entrance into the village has been blocked off by police.
An investigation into the circumstances of the incident has already begun.
Likud MK Miri Regev condemned the arson attack, saying, "No to price tag - it is forbidden to take the law in to your own hands."
She implored the leadership in Judea and Samaria to "get the message across to the extremist Jewish minority that is trying to inflame the situation."
Separately, police said, unknown assailants threw a petrol bomb overnight at an ancient synagogue in Shfaram, a predominantly Muslim and Christian Arab town in northern Israel. There was small-scale damage and police were investigating.
The fire comes less than two days after IDF soldier Sgt. Almog Shiloni and Dalya Lamkus were killed in separate terror attacks within a matter of hours, the former in Tel Aviv and the latter near Alon Shvut in the West Bank. Several other victims were badly wounded in the attacks.
Islamic Jihad claimed responsibility for both attacks. Police and security services went on high alert for copycat attacks across the country.
The “Knife Intifada” has begun, Palestinians tweeted and re-tweeted.
Ben Hartman and Reuters contributed to this report.