By Amos Harel, Avi Issacharoff and Akiva Eldar, Haaretz Correspondents, and Agencies
Tens of thousands rallied in Khan Yunis, Gaza City and Rafah in support for their side, but much smaller numbers were involved in the clashes.
Seven people were wounded by gunfire and eight by stones in the rallies, according to reports from Hamas and hospital officials. Three others were treated after being trampled in Gaza City, medical officials said.
In Khan Yunis, Fatah loyalists touching off the melee by chanting, "Shia, Shia" - a reference to the Shiite Muslims who control Iran, Hamas' backer.
Hamas gunmen opened fire and threw stones, and then Fatah returned fire. Masked Hamas gunmen from a nearby refugee camp came into the town to reinforce armed men already there.
In Rafah, Hamas gunmen said they came under fire from Fatah, while Fatah officials accused Hamas militiamen of firing on a peaceful demonstration.
The gunbattles in Gaza City took place near the home of Fatah strongman Mohammed Dahlan. Hamas accuses Dahlan of masterminding an assasination attempt against Palestinian Prime Minister Ismail Haniyeh of Hamas earlier this week.
On Friday, Hamas' Damascus-based political chief Khaled Meshal urged Hamas members to "practice restraint" and avoid being "dragged into a civil war" amid worsening factional violence in the PA.
At least 31 Hamas supporters were wounded, some critically, when gunmen from Abbas' Fatah movement opened fire on a Hamas rally in the West Bank city of Ramallah on Friday, leading a senior Hamas leader to accuse Abbas of launching a war.
"I call on our brothers in Hamas to practice restraint ... to protect Palestinian blood," Meshal said in a live radio interview from his base in the Syrian capital of Damascus. "Our battle is against the occupation, and we will not be dragged into a civil war."
But a senior Hamas official in Gaza on Friday accused Abbas of sparking a civil war between Fatah and Hamas.
"What a war Mahmoud Abbas you are launching, first against God, and then against Hamas," senior Hamas leader Khalil al-Hayya told a Gaza City rally of 100,000 Hamas supporters, who chanted "God is Greatest" and fired guns into the air.
On Thursday night, a convoy in which Haniyeh was riding came under fire as he crossed the border from Egypt into Gaza. Hamas charged that the shooting was an asssassination attempt by Fatah.
Haniyeh was more conciliatory at the rally Friday, appealing for "national unity," but he stopped short of explicitly calling for calm. Haniyeh called on both factions to "preserve Palestinian blood."
Fatah and Hamas gunmen exchanged fire on the streets of Gaza City and the West Bank city of Ramallah on Friday.
After an urgent cabinet meeting convened by Haniyeh, Interior Minister Saeed Seyam told reporters the government had decided to open an investigation into the attack on the prime minister and "pursue the criminals and bring them to justice."
Abbas announced Saturday that he has decided to call fresh elections as soon as possible, drawing condemnation from the ruling Hamas movement.
Senior Abbas aide Saeb Erekat, also of Fatah, said Hamas was to blame for the violence, and warned against any reprisals for the attack on Haniyeh.
"We hold Hamas fully responsible for what happened Thursday at Rafah, both the chaos and destruction, and Hamas is fully responsible for whatever may harm [top Fatah official Mohammed] Dahlan or any other Palestinian citizens," Erekat told reporters in Ramallah.
Hamas has accused Dahlan of orchestrating the attack on Haniyeh. Fatah sources accused the Hamas' highest ruling body, the Shura Council, of ordering the assassination of Dahlan and seven other Fatah leaders in Gaza: Maher Makdad, Samir Masharawi, Jamal Abu Jadian, Samiah Madhoun, Abd-Alhakim Awad, Tawkfik Hussah and Abu Ali Shahin.
In Washington, without referring to the assassination allegation, U.S. State Department spokesman Sean McCormack said differences among Palestinians "should be resolved within the context of the Palestinian political system."
"What you are seeing," he added, "is a rise in tensions that really emanates and is the direct result of the inability of Hamas to effectively govern in the Palestinian areas."
The fighting damped celebrations Friday marking the 19th anniversary of Hamas' founding. However, the Islamic militant group pushed ahead with its rallies, and about 70,000 loyalists gathered at a stadium in Gaza City on Friday afternoon, cheering wildly, sobbing and firing in the air when Haniyeh arrived flanked by more than 50 armed bodyguards.
"We joined this movement to become martyrs, not ministers," Haniyeh declared in a fiery speech, referring to Hamas loyalists' willingness to die for their cause, often in suicide attacks on Israeli targets.
He then left for an emergency session of the Hamas-led Cabinet, called to
discuss the escalating unrest.
A Ramallah resident told Israel Radio that one person was killed in the clashes in the city, but the report could not be immediately verified.
Abbas' security forces, dressed in riot gear, used clubs and rifles to beat back Hamas demonstrators before shooting broke out.
The shooting in Gaza City began Friday afternoon when masked Hamas gunmen began waging battle with Fatah-allied Palestinian police at their post in the middle of the city. The four-minute battle sent civilians running for cover. It was unclear if anyone was hurt.
The clashes took place a block away from Dahlan's home.
In a show of force, Hamas had earlier deployed armed militants carrying automatic rifles and rocket-propelled grenade launchers in key parts of the Gaza Strip on Friday.
Haniyeh bodyguard killed, over two dozen hurt in Thursday attack
The attack on Haniyeh's convoy took place upon his return from a fundraising tour of the Middle East. Haniyeh's bodyguard was killed in the shooting, and more than two dozen people - including Haniyeh's son, Abdel Salam, and his political adviser, Ahmed Yousef - were wounded. The incident deepened factional violence that has pushed the rival Hamas and Fatah parties closer to civil war.
Haniyeh has threatened to "deal with" shots fired at his convoy, but did not provide further details. Angry Hamas officials on Friday pointed the finger at Dahlan - who denied the accusation, according to Israel Radio.
Ismail Radwan, a Hamas spokesman, told a news conference that Dahlan "planned and organized the [attempted] assassination of Palestinian Prime Minister Ismail Haniyeh."
"The dirty hands which assassinated and wounded the body guards of the prime minister and attacked the prime minister's convoy will not escape punishment," said Radwan. He offered no evidence of Dahlan's involvement.
Fatah dismissed the accusations against Dahlan.
"These accusations are not true, as long as no investigation to find out has been conducted," Tawfik Abu Khousa, a Fatah spokesman, said, calling for an official investigations. "These accusations are posing a grave threat to Palestinian unity."
The shooting attack took place after Haniyeh was held up at the Rafah crossing between Egypt and Gaza for more than seven hours. Israel ordered the closure to prevent him from bringing in $35 million in cash raised on a trip to Muslim states. Haniyeh was allowed to enter Gaza on Thursday night after leaving the funds in Egypt.
Arriving home around midnight, Haniyeh appeared furious over the gunfire at his convoy. "We know the party that shot directly at our cars, injuring some of the people with me... and we also know how to deal with this," he said, but did not explain further.
Hamas spokesman Fawzi Barhoum said the shooting was an attempt to assassinate Haniyeh, and held the Fatah-allied Presidential Guard responsible.
"The Presidential Guard controls the Palestinian side [of the border terminal]. There are no other gunmen there. They are responsible for security of the border," Barhoum said. "We say there was a clear assassination attempt."
Wael Dahab, a spokesman for the Presidential Guard, said many gunmen were in the area and that it was difficult to control the situation. "Our men did not start the shooting, they did not shoot, and there were many people carrying guns," he said.
Abbas expressed regret for the shooting, according to the Palestinian news agency, WAFA.
About 50 gunmen greeted Haniyeh at his home in a refugee camp next to Gaza City, firing in the air and throwing candies.
The latest round of Hamas-Fatah fighting erupted Monday with the brutal
killing of the three small children of a Fatah security official and continued Wednesday with the gangland-style execution of a Hamas judge.