Palestinian officials say Jewish settlers have set fire to a mosque in the occupied West Bank.
Residents of Beit Fajjar, near Bethlehem, said a group of settlers went into the mosque overnight and set fire to carpets and copies of the Koran.
Reports say the word "revenge" was scrawled on the wall in Hebrew.
A spokesman for the Israeli military said it was taking the burning of the mosque very seriously, and was trying to apprend the "law-breakers".
The BBC reports the mayor of a nearby settlement has condemned the attack and said those carrying it out must have been "extremists".
The assault comes as Palestinian-Israeli peace talks have faltered over the issue of settlements.
Israel has occupied the West Bank, including East Jerusalem, since 1967, housing nearly 500,000 Jews in more than 100 settlements. Some 2.5 million Palestinians live in the West Bank.