Senior Fatah sources reported late Thursday that its National Security Force arrested seven Iranian weapons experts working in the service of Hamas in Gaza.

According to Fatah, the arrests were made during a raid on the Islamic University in Gaza City. The Fatah forces apprehended some 1,400 firearms and missiles found at the site.

Six Palestinians were killed and at least 65 were wounded, including two children, on Thursday during renewed clashes in the central Gaza Strip between armed Hamas and Fatah militants.

The clashes marred efforts to shore up a truce put into effect three days ago, that brought relative quiet to Gaza after days of deadly factional violence. Sporadic isolated clashes have continued since the beginning of the truce.

Five Fatah militants were killed in the central Gaza refugee camp Bureij on Thursday afternoon, when Hamas gunmen ambushed what the Islamic group alleged was a convoy carrying weapons from Egypt into the Gaza Strip, intended for the presidential guard.

Three of the fatalities were named as members of Palestinian Authority Chairman Mahmoud Abbas' Presidential Guard - Arafat Halibi Al-Mushlah, 24, Murad Al-Tala, 23, and Mohammed Haitab.

Another of the fatalities was named as National Security Force member Akrami Rnain, 23, and a fifth was named as Palestinian military intelligence member, Osama A-Shinani, 25.

The sixth fatality has still not been identified, and was apparently a child.

Later Thursday afternoon, Hamas militants fired mortar shells near Abbas' residence in Gaza City and nearby street battles sent residents fleeing in terror. Some left their cars idling while they sought shelter.

Masked gunmen took up positions on rooftops, while others took cover in alleyways below. Abbas was not in Gaza at the time.

Separate gunbattles then broke out in Gaza City and in northern Gaza outside a military intelligence post. Security officials said Hamas militants fired a rocket at the post and then sacked it, injuring five members of the security forces. At least two Hamas supporters were wounded, Hamas said.

A Fatah member was kidnapped in northern Gaza during the clashes, and one security officer was wounded, security officials said.

Earlier Thursday, an additional ten Palestinians were wounded during a Hamas attempt to take over a military intelligence headquarters in the northern Gaza Strip.

Hamas attacks Fatah convoy Abbas's Fatah faction said the four-truck convoy, which set off from the Kerem Shalom crossing with Israel, was carrying medical equipment and tents, and accused Hamas of plunging a 3-day-old Palestinian ceasefire into "grave danger."

The ceasefire had largely stopped a surge in internal fighting in the territory in which at least 34 Palestinians had been killed.

A battle raged between Hamas gunmen and presidential guards accompanying the convoy, according to residents in the area.

"A real war is taking place, gunmen are using the heaviest arms they have," a witness said.

Sources in the governing Hamas movement said the trucks were carrying weapons for the 4,000-man presidential guard, a force loyal to Abbas and his Fatah faction.

"Hamas's heroes have commandeered arms shipments that came through Kerem Shalom as part of the fight against the Palestinian people," a presenter on a Hamas radio station said.

Fatah spokesman Tawfiq Abu Khoussa said the convoy was carrying generators, tents and medical equipment.

"There are no weapons at all," Abu Khoussa told the Reuters news agency, adding the ambush "represented a grave danger to the continuation of the (ceasefire) agreement"

Asked about the convoy's cargo, a Palestinian security official declined to comment. A senior Israeli official said she knew trucks had entered the Gaza Strip but did not know their contents.

Gunmen open fire on Hamas Palestinian gunmen opened fire at Hamas officials in two separate attacks early Thursday.

Early Thursday, unknown gunmen opened fire at Hamas spokesman Fawzi Barhoum as he drove with three bodyguards in his white sedan toward an impromptu checkpoint near Gaza City, Hamas said. There were no casualties. A Hamas announcement blamed "coup-seekers," a reference to militants from the rival Fatah party.

"This is a violation of the [truce] agreement," Barhoum said. He reported the incident to Egyptian mediators and the gunmen removed their checkpoint, he said.

Later Thursday, gunmen in a car shot at Islam Shahwan, a spokesman for a Hamas militia, Shahwan said, blaming the shooting on Fatah-affiliated security officers. One Hamas member was wounded, he said.

The incidents - and another shooting Wednesday that critically wounded a Fatah man - didn't unravel the cease-fire, declared early Tuesday by leaders of Fatah and Hamas. The truce is meant to bring an end to internal fighting that has left more than 60 Palestinians dead since early December.

U.S. President George W. Bush has committed $86 million to provide training and non-lethal equipment to forces loyal to Abbas. Guns and ammunition are being supplied by key U.S. allies Jordan and Egypt, with Israeli approval, Israeli officials say.

Diplomats say Abbas' military build-up was meant to counter strides by Hamas in smuggling in more powerful weapons into Gaza for its fast-growing "Executive Force" and armed wing, known as the Izz el-Deen al-Qassam Brigades.