Arab states say the work could damage the foundations of the mosque, the third holiest site in Islam.
Israeli authorities say the building work, begun on Tuesday, is being carried out to replace a centuries-old ramp 60 metres away.
'Day of anger'
A day of "anger" on the Muslim day of rest has been called by Tayssir al-Tamimi, the Palestinian chief justice, who on Tuesday called for "all Palestinians to go and protect al-Aqsa against Israeli plans that aim to destroy the mosque".
Thousands of Muslims regularly attend Friday prayers at the site, known to Muslims as the Noble Sanctuary.
For Jews it is the
International observers have said that the excavation work risks igniting a third Palestinian intifada [uprising] against
A controversial visit to the al-Aqsa mosque compound in 2000 by Ariel Sharon, then leader of the Israeli opposition, sparked the most recent intifada.
Micky Rosenfeld, an Israeli police spokesman, said entrance to the Friday prayers would be restricted.
West Bank Palestinians would be barred, as would Israeli Arab and east
An Arab group at the United Nations appealed on Thursday to the UN security council to stop the excavation work.
In a statement, Arab ambassadors asked the Security Council "to take immediate and urgent measures to put an end to Israeli violations and to guarantee its respect for international law and security council resolutions".
They said in a statement they "denounced the Israeli occupation authority's escalation of its aggression on Islamic endowments in occupied
Israeli officials have said some Muslim commentators are using the renovation work as a pretext to stoke anger against
Speaking during a visit to
Muslims believe the compound, home to the golden-capped Dome of the Rock shrine and al-Aqsa mosque, is where the Prophet Muhammad ascended to heaven.