Arsonists suspected of being radical Israeli settlers damaged part of a Palestinian mosque early on Monday in a village near the West Bank city of Hebron, setting fire to rugs and copies of the Koran and scrawling the word “revenge” in Hebrew on a wall, police officials and witnesses said.

Palestinian residents of the village, Al Fajjar, said they saw what they described as an Israeli car speeding away before dawn.

Monday's vandalism was the fourth attack on a West Bank mosque in the past year. Last May, Palestinians accused settlers of setting fire to a mosque in the village of Libban al-Sharqia. Israel said the blaze was probably caused by a spark during building work.

No charges have been brought for any of the previous incidents.

“In that period of time, there has not been a single culprit found, for any of these attacks or actions,” Hanna said.

Human-rights groups say the Israeli government does not take the attacks seriously enough.

A report by Amnesty International, the London-based rights group, found that "impunity remains the norm" for settlers accused of vandalism and physical attacks on Palestinians.

"This is not the first time that settlers have burned a mosque. This started when they burnt the Al-Aqsa Mosque in 1969 and it still continues," Muhammad Ayash, head of the Islamic Waqf in the district of Bethlehem, said.

Hanan Ashrawi, a member of the PLO executive committee, accused the settlers of using extremist and violent behaviour to try to escalate tensions. She also condemned the Israeli army for standing idly by and protecting the settlers.

On one wall of the mosque were the words, in Hebrew, “A mosque must be burned.” There was no claim of responsibility.