By Maayan Lubell, Ali Sawafta and Nidal al-Mughrabi
JERUSALEM Reuters) - After weeks of relative calm in Jerusalem, friction between Israel and Palestinians over unauthorized prayers by Jewish visitors in the Al-Aqsa mosque compound is raising the stakes at one of the Middle East's most volatile holy sites.
At the compound, Islam's third holiest site after Mecca and Medina and Judaism's most sacred, only Muslim worship is allowed. Jews may not pray there. But some do. And increasingly so, stoking anger among Palestinians.
Tensions between Palestinians and groups of Jewish visitors are never far away but the risks of confrontation have risen ahead of Sunday when Jews mark Tisha B'Av, a holy day of mourning for ancient temples which once stood on the site.
On Friday, Islamist militant group Hamas urged Palestinians to defend the mosque on Sunday "with all possible means". The mosque's preacher, Sheikh Ekrima Sabri, called on faithful to attend prayers and foil "radical Jews' plan to storm the site".
Although only a small minority of Jews are active in trying to pray on the elevated stone plaza where the mosque is situated, visits by Jews have increased this week, some whispering prayers at the edge of the compound.
The shutdown of border crossings with the Gaza Strip, following the arrest of a senior Palestinian militant leader this week, has further raised the temperature.
Clashes at Al-Aqsa, most recently during the holy Muslim month of Ramadan, have upset the Islamic world and caused worry among foreign powers about religion fanning the flames of a national conflict they want settled by territorial compromise.
There is an unwritten "status quo" agreement on Al-Aqsa that is meant to stave off any "holy war".
Increasingly challenged by nationalist Jews, the pact preserves a rule effectively in place since Saladin's 1187 defeat of the Crusaders: Non-Muslims can visit the compound but only Muslims can worship there.
But while administration of the compound is in Muslim hands, Israel oversees security.
Prime Minister Yair Lapid says Israel is fully committed to the accord, designating those who defy it as fringe extremists who "slip through the cracks".
But confrontations between Jewish visitors, who defy the ban sometimes bearing flags and praying openly, and Palestinians who try to drive them off with verbal and sometimes physical attacks have raised criticism that the status quo is not being properly enforced.
While Israeli police say they must intervene when violence occurs, Palestinians say the police tacitly allow Jewish prayers to continue, use excessive force against Muslims and disrupt their worship inside the mosque.
"We don't want religious war and we don't want a religious conflict. We want Jerusalem to be calm and peaceful," said Sheikh Azzam Al-Khatib, director of the Waqf, the Islamic trust which oversees the site, "but harm to Muslims' faith will not be allowed."
Palestinian fears of Israeli encroachment are reflected in the language of regular calls to defend against "storming" of the site which they say is exclusively Muslim.
Muslims believe the Prophet Mohammad prayed in the compound that houses the more than 1,000-year-old Al-Aqsa mosque and Dome of the Rock shrine - before ascending to heaven, and they call it the Noble Sanctuary.
For Jews, who know it as the Temple Mount, it is their holiest site because it housed the two Jewish temples of antiquity. According to Jewish tradition, it is also where Abraham built Isaac's altar.
But following Israel's victory in the 1967 Middle East war, when Jerusalem's walled Old City was captured from Jordan, the state's secular socialist leaders opted to keep the status quo guaranteeing Muslim stewardship of the site.
Mainstream Orthodox Judaism has also ruled the plaza off limits for Jews for religious reasons lest they tread the sacred grounds of the temples' Holiest of Holies. Instead, Jews overwhelmingly pray at the Western Wall, just below the compound, where worship is permitted.
But over recent decades, some nationalist rabbis have gradually eased the ban and Waqf officials say that more than 100 Jews now ascend a passageway to the compound nearly every day. Though often the same people, they are far more than the handful of daily visits 20 years ago.
While Jordan, which retained its responsibility for the Waqf, says Israel has been chipping away at the status quo, nationalist Jews who demand the right to pray there want it scrapped altogether.
"The state is breaching freedom of worship at the holiest place to Jews," said Arnon Segal, an advocate for prayer at the site who is vying for a seat at the Israeli parliament in November's election.
Police occasionally allowing some to get away with a whispered verse simply isn't enough, said Segal.
Tomer Persico, an expert on contemporary Judaism at the Shalom Hartman Institute, said that while some Jewish visitors simply seek a spiritual experience, many "want to demonstrate ownership and sovereignty of Israel on the Temple Mount".
Although that view is championed by a tiny group that is largely viewed by the Israeli establishment as troublemakers, it is echoed by far-right Israeli lawmakers and heard by Palestinians far beyond Jerusalem.
For many Palestinians, who seek east Jerusalem - taken by Israel in the 1967 war - as the capital of a future state, the visits amount to an assault on one of the central elements of their own identity.
Palestinian youths who wave flags and throw stones in confrontations with police "are driven by enthusiasm and the feeling of responsibility toward Al-Aqsa when they see Israelis going in", Palestinian political analyst Talal Okal said.
(Additional reporting by Ammar Awad and Dan Williams; Editing by James Mackenzie and Mark Heinrich)