GAZA CITY, Gaza Strip - The killing of a 10-year-old Palestinian girl in a Gaza schoolyard Monday prompted Islamic militants to fire mortar shells at Jewish settlements and endangered an unofficial cease-fire between Israelis and Palestinians.

Although the circumstances of Norhan Deeb´s death were unclear, the violence strained the recent atmosphere of goodwill between Israeli Prime Minister Ariel Sharon and the new Palestinian leader, Mahmoud Abbas.

Despite the heightened tensions, top Israeli and Palestinian security officials met later Monday to work out the details of a handover of several West Bank towns to Palestinian control.

The girl was killed in the courtyard of a U.N. school in the Rafah refugee camp near the Egyptian border, a frequent flashpoint of violence between Israeli troops and Palestinian gunmen.

Palestinian witnesses said the gunfire came from a nearby Israeli military position along the border.

However, the Israeli military said the girl was not hit by Israeli fire. Soldiers opened fire in two cases, an army spokesman said, but neither was in the area where the girl was shot. "According to our examination, the girl apparently was not shot by Israeli army gunfire," the military spokesman´s office said.

Palestinian revelers had been shooting into the air in the area, celebrating their return from the Hajj pilgrimage to Mecca, a military official said on condition of anonymity.

Residents, however, said no such celebrations took place.

Dr. Ali Moussa, the physician who treated the girl, said she was hit by a bullet in the face, but initial reports by paramedics that she had been killed by tank fire were wrong.

Witnesses said the girl was shot in the head as she and other pupils lined up in the schoolyard for afternoon assembly.

"I didn´t hear any shooting. Suddenly, I heard Norhan screaming. Then she fell down," said Aysha Khateeb, a classmate who was wounded in the hand. "I looked at my hand and saw blood."

She spoke to The Associated Press from her hospital bed and burst into tears as the covered body of her classmate was wheeled by on a stretcher.

Mariam Abu Shamala, the school´s deputy principal, said the students were rushed inside after the shooting. During a break later in the day, she said the terrified students refused to go outside.

"Her friends put flowers on the dead girl´s desk. They kept her bag, and put her uniform on it," Abu Shamala said.

Johan Eriksson, a spokesman for the U.N. Relief and Works Agency, said U.N. officials weren´t able to definitively identify the source of the gunfire, but that all signs pointed to the Israeli troops.

"The only firing that took place at that time in the entire Rafah area" came from the direction of an Israeli observation post, he said.

Residents who live near the observation post said they heard firing from the area. However, none of the witnesses actually saw any shots being fired.

Hours later, Palestinian militants fired at least six rounds of mortar shells at Jewish settlements in Gaza, damaging one house in the Neve Dekalim settlement, the Israeli army said. The Islamic group Hamas claimed responsibility, saying it was avenging the girl´s death.

Later Monday, Hamas issued a statement threatening to retaliate against Israel "if the crimes continue," implying that it would hold its fire if no further violence occurs.

The violence upset a recent lull in fighting.

Abbas has won a commitment from militant groups to stop attacks and deployed thousands of officers throughout Gaza over the past 10 days to ensure the quiet. Although no formal cease-fire has been declared, Israel has scaled back military operations in return.

In the Israeli-Palestinian security meeting that began after nightfall Monday, Israeli Defense Minister Shaul Mofaz and Palestinian negotiator Mohammed Dahlan were completing preparations for a security handover in the West Bank.

Palestinian police commanders said they were told to prepare to take control of four West Bank towns - Ramallah, Qalqiliya, Tulkarem and Jericho - as soon as Wednesday. However, Israeli officials said no steps would be taken ahead of a meeting of the Israeli Security Cabinet on Thursday.

Palestinian security officials said they were told by their Israeli counterparts that in addition to leaving West Bank towns, troops would take down some roadblocks, rolling back security measures imposed after violence erupted in September 2000.

Israeli forces reoccupied West Bank towns in April 2002, after a series of bloody suicide bombings, but have pulled back to the outskirts of population centers in most areas since then.

Abbas and Sharon are heading toward their first meeting since 2003, when Abbas was prime minister. Feb. 8 has been set as a tentative date for the summit, two days after a scheduled visit by Secretary of State Condoleezza Rice.

In Jerusalem, Jewish settlers and their supporters protested outside parliament for a second day Monday against Israel´s planned withdrawal from Gaza and part of the West Bank, demanding Sharon hold a referendum on his plan.

More than 100,000 settlers participated in a huge demonstration against the withdrawal plan on Sunday night. Several hundred spent the night in tents outside parliament. (Copyright 2005 Associated Press. 01/31/05)