JERUSALEM (AP) – Thousands of Israeli police mobilized at Jerusalem’s most sensitive holy site Sunday but confronted only a handful of Jewish extremists intent on scuttling a Gaza pullout by tying up security forces. In Gaza, militants fired dozens of mortar shells after Israeli forces killed three teenagers.

Israeli Prime Minister Ariel Sharon, speaking on a plane taking him to Monday’s meeting with President Bush, said the mortar fire “is a flagrant violation of the understandings” reached at the February truce summit with Palestinian leader Mahmoud Abbas.

“And this will be a central issue to be raised in my talks with President Bush,” Sharon said.

Police arrested 31 extremist Jews who planned to demonstrate Sunday in the Old City of Jerusalem, along with a West Bank Hamas leader who spoke at the holy site. But the 10,000 demonstrators pledged by organizers never materialized. Only a few dozen showed up.

Despite the low turnout, Israeli officials acknowledged the protesters appeared to have accomplished their goal of showing how easy it will be to divert large numbers of troops from their main mission this summer – the planned Gaza pullout.

At the center of the drama is the most sensitive and hotly disputed holy site in the Holy Land – a hilltop known as the Temple Mount to Jews and Noble Sanctuary to Muslims.

Clashes at the site could ignite violence across the region, explaining the presence of 3,000 riot-ready Israeli police around the walled Old City, preparing to confront a handful of demonstrators.

Extremist Jews who make up a new group called “Revava,” a biblical word that means 10,000, stated openly that their goal is to storm the sensitive site in July, when thousands of Israeli police and soldiers are in Gaza to evacuate 9,000 settlers – forcing Israel’s leaders to pull the forces from Gaza, send them to Jerusalem and, in that way, stop the pullout. The Sunday protest, they said, was just a test.

In anticipation of the protest, hundreds of Palestinians spent the night in the mosque compound, ready to confront Jewish demonstrators.

Hassan Yousef, a senior West Bank leader of the violent Islamic group Hamas, entered the mosque compound despite tough police restrictions, including a ban on male worshippers younger than 40 and those from the West Bank.

“Al Aqsa is in danger,” Yousef said.

Yousef was detained on his way back to the West Bank, police said. He was released recently from an Israeli prison after a two-year term and has been a relatively moderate voice in the Islamic group since then.

Outside the Old City walls, hundreds of young Palestinians scuffled with baton-wielding police, who kept them away from the shrine. Two Palestinians were hurt, with one suffering a head injury after being hit by a club. Eventually, the Palestinians knelt in orderly lines on the road ringing to Old City to perform Muslim prayers.

In the West Bank, thousands of Palestinians took to the streets. In Nablus, some 3,000 Palestinians, including dozens of armed men who fired in the air, marched through the streets. In Hebron, about 1,000 Palestinians marched and chanted slogans about protecting the mosque.

Israel has stepped up security in Jerusalem recent days. Security officials say they fear hard-liners will attack the hilltop shrine.

Carmi Gilon, former head of the Shin Bet security service, said that if there is such an attack, Israel would find itself at war with the entire Muslim world.

“Of all the means … of stopping disengagement, no doubt the Temple Mount is the doomsday weapon,” he told Israel Radio.

In Gaza on Sunday, Palestinians in Gaza fired dozens of mortars and rockets at Jewish settlements, retaliation for Israel’s killing three teenagers on the Gaza Egypt border a day earlier, endangering a two-month truce.

Israeli Defense Minister Shaul Mofaz called Abbas and demanded that he deploy police to stop the mortar and rocket fire, his office said. Israeli media reported that the talk was difficult, and Mofaz warned that if the fire is not stopped, all the summit understandings could collapse.

Thousands of mourners, led by gunmen firing in the air, buried the three Palestinian teens. Israelis and Palestinians offered widely varying accounts of the incident, the bloodiest there since the truce was declared.

Ahmed al-Jazar, 14, said he and four classmates were playing soccer on the outskirts of Rafah on Saturday when one of the boys shot the ball close to a wall Israeli troops built between the patrol road and the Rafah camp. Two of the boys ran after the ball.

“We heard the sound of shooting,” al-Jazar said Sunday.

He said he told a friend next to him to stay down, but his friend ignored the advice.

“He got up … and was shot in the chest,” al-Jazar said.

The Israeli military said soldiers opened fire after they saw the teens sneaking into the no-go zone, suspecting they were arms smugglers.

In a separate development, the head of the Palestinian Election Commission said legislative elections set for July will have to be postponed if parliament fails to adopt a new election law within a week.

Senior members of Abbas’ Fatah moving have been urging him to delay the vote, amid fears of a resounding victory by the rival Hamas group.

If held as planned on July 17, the vote would take place several days before the Gaza withdrawal. Fatah could win some political capital if the elections are held after the pullout, which could be presented as an accomplishment by Abbas.

AP-ES-04-10-05 1935EDT