Gunmen fired at the house of Palestinian Prime Minister Ismail Haniyeh of Hamas early Monday and warring factions threw militants to their deaths from high-rise buildings, in a dangerous escalation of infighting in Gaza.

There were no reports of casualties in the attack on Haniyeh's house in the Shati refugee camp next to Gaza City. His office wouldn't say whether he was inside when the house and surrounding area came under heavy fire for about 15 minutes from a nearby high-rise building. But his wife, children and grandchildren were, his family said.

It was the first time in a month of fighting between Hamas and the rival Fatah group that Haniyeh was an apparent target.

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Before daybreak Monday the sides reached an agreement to stop the clashes, and Fatah-linked security forces began pulling back from points of friction around the Gaza Strip. But several such cease-fires in recent weeks have been short-lived. Shooting could still be heard at several points around Gaza City as residents awoke Monday.

The fighting took a grisly turn on Sunday, when Hamas militants kidnapped a member of the elite presidential guard of Palestinian President Mahmoud Abbas of Fatah, took him to the roof of a 15-story apartment building and threw him to his death.

That set off skirmishes throughout the city, including gun battles and shelling. Fatah militants surrounded the house of a Hamas mosque preacher, fired rocket-propelled grenades at the four-story building and then entered, firing at the preacher, and taking him away. Later, his body was brought to a hospital. Hamas pledged revenge.

And just before midnight, a Hamas activist was thrown off the 12th floor of a building and killed, security officials said. Four other Hamas men in the building were shot and wounded, bringing the day's toll to three dead and 36 wounded, medical officials said.

A Hamas militant wounded Friday in southern Gaza infighting also died on Sunday.

The two sides have been locked in a violent power struggle since Hamas ousted Fatah from power in January 2006 elections. Hamas brought Fatah into its government in March in an effort to quell the internal strife, but the fighting reignited in mid-May over an unresolved dispute over who controls the powerful security forces.

Fifty-five people have been killed in the latest outbreak of violence, most of them militants. A truce declared two weeks ago was meant to end the clashes, but last week the fighting resumed around the southern Gaza city of Rafah.

Both Abbas and Haniyeh called on gunmen to pull back from streets and rooftops to allow about 24,000 Gaza 12th grade high school students to start their final exams on Monday. The Education Ministry said Monday the tests would go ahead as planned.

Daliya Naji, a 16-year-old high school senior, said the fighting in Gaza had kept her awake all night. "I am a good student, but I feel my brain is empty," she said. "I can't think any more and I don't know what to do."

She said she hoped she would pass her exams in order to be accepted to a university in Egypt. "At least it will be my ticket out of Gaza," she said.

The deadly infighting has overlapped with new clashes between Israel and Palestinian militants who have been firing rockets at southern Israeli communities bordering Gaza.

Early Monday, Palestinian militants fired five rockets into southern Israel, the army said. There were no injuries, but the Education Ministry said high-school students in the border town of Sderot were moved to towns out of rocket range in order to take their final exams.

On Sunday, Israeli political and military leaders pledged to keep up the pressure on Gaza after Palestinian militants infiltrated Israel a day earlier in a failed attempt to capture a soldier.

"I said a week ago that our operations in Gaza will continue as long as it takes to block the terrorists attempts to infiltrate and the Qassam rockets," Prime Minister Ehud Olmert told his Cabinet.

The military chief of staff, Lt. Gen. Gabi Ashkenazi, favors more intensive military activity in Gaza, but not a full-scale invasion, defense officials said Sunday. They spoke on condition of anonymity because military policy is confidential.

Israeli forces briefly entered southern Gaza late Sunday in what the military said was a routine, small-scale operation aimed at demonstrating a presence and deterring rocket fire.

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