"As the police entered the compound masked youths fled inside the mosque and threw stones at the force," a police statement said.
Police said they entered the hilltop compound to ensure that Muslim youths massing there did not harass Jews or tourists during the morning visiting hours. The site is sacred to both Jews and Muslims.
The statement added that three protesters were arrested and visits went ahead as planned to the site, the third- holiest in Islam and venerated by Jews as the Temple Mount.
Non-Muslims are allowed to visit the compound, but Jews must not pray or display national symbols for fear of triggering tensions with Muslim worshippers.
Muslims fear Israel will seek to change rules governing the site, with far-right Jewish groups pushing for more access and even efforts by fringe organisations to erect a new temple.
Israel seized east Jerusalem, where Al-Aqsa is located, in the Six Day War of 1967 and later annexed it in a move never recognised by the international community.