Palestinian officials say more than 150 people have been injured in clashes with police at the Al-Aqsa mosque in Jerusalem.
Israeli police say they moved in because rioters were setting off fire crackers and throwing stones towards Jewish worshippers.
The site is Islam's third most sacred - and the most sacred for Jews.
100s of Palestinians have been arrested.
Ahmad Tibi was there and says the scenes were shocking:
"It was brutal. Brutal reaction of the Israeli police and brutal attack against prayers inside the mosque. Inside the Al-Aqsa mosque".
