Thousands of Israeli police have been deployed in Jerusalem as Palestinian groups call for protests over tensions at the al-Aqsa mosque.

The Islamist group Hamas called for a "day of rage", local media said, while its rival Fatah urged peaceful protests over access to the key holy site.

Sporadic clashes in recent weeks are apparently due to Palestinian fears of extremist Jews gaining entry.

The tensions come as US envoy George Mitchell visits the region for talks.

US attempts to restart peace negotiations appear to have stalled over Israel's refusal to meet US and Palestinian demands that it freeze all settlement activity in the West Bank.

"We are determined, persevering, and we recognise the complexities and the difficulties," Mr Mitchell told reporters before meeting Israeli Defence Minister Ehud Barak on Thursday.

Israel has made clear that it intends to keep building in East Jerusalem, where the Palestinians want the capital of their future state.

The Palestinian Authority, dominated by Fatah, has accused Israel of seeking to "Judaise" East Jerusalem, and of allowing extremists access to the al-Aqsa mosque compound while denying it to Muslims.

The Islamic Movement - a political organisation based in Israel - has urged Muslim citizens of Israel to flock to Jerusalem to "defend al-Aqsa".

Israeli police briefly detained its leader, Sheikh Raed Salah, on Wednesday, accusing him of incitement and have banned him from entering Jerusalem.

On Friday Israeli police maintained restrictions under which only female worshippers and men over the ager of 50 were permitted to enter the mosque area.

The compound, also know as the Temple Mount, contains the holy sites of both the al-Aqsa mosque and the Western Wall. I has been a flashpoint for violence in the past, including the beginning of the intifada or uprising that started in 2000.

Sporadic clashes between rock-throwing Palestinians and Israeli police near the site and at locations in East Jerusalem have taken place on several days since 30 people were injured in rioting in late September.

The initial violence broke out when Palestinians threw stones at visitors to the compound they believed were right-wing Jews, although Israeli police say they were French tourists.