Hamas gunmen early Sunday stormed a training camp in the Gaza Strip used by Palestinian Authority Chairman Mahmoud Abbas' presidential guard, sparking gunbattles that left one officer dead and several others wounded.

The attack was the first of its kind against the elite U.S.-backed Palestinian force, made up of about 3,500 security men.

The assault touched off a fierce, 20-minute battle. The gunmen fled after reinforcements were sent to the base from other presidential guard camps, security officials said.

One guard stationed at the base gate was killed, and three guards were wounded, according to a statement from the guards.

A presidential guard official denounced the attack as an assault on the "symbol of Palestinian legitimacy."

Abu Ubaida, a spokesman for Hamas's armed wing, denied the group had been involved in the attack, saying "This is a wrong and irresponsible accusation."

The base is located about 700 meters from the PA chairman's residence and office in Gaza City. Abbas was in the West Bank town of Ramallah at the time of the attack.

Before arriving at the base, the gunmen attacked an electricity transformer in the area, cutting off power to the base and nearby houses, the presidential guard said.

Hamas: Elections bid is 'defeat and submission' to Zionists The Palestinian government's ruling Hamas party on Saturday dismissed Palestinian Authority Mahmoud Abbas' call for early election, calling it a bid by Abbas to overthrow the government

"The Palestinian government rejects this call for early elections and considers it a coup against Palestinian legitimacy and the will of the Palestinian people," the government said in a statement Saturday.

Hamas legislator Mushir al-Masri said the group considers early elections illegal, and called Abbas' speech announcing his plans one "of defeat and submission to the Zionist enemy."

The rival Fatah and Hamas factions both held processions Saturday after the evening prayers in the mosques, and clashed with each other in Rafah and Khan Yunis, after Palestinian Authority chairman Mahmoud Abbas called for early elections for the PA presidency and parliament.

Abbas announced Saturday that he has decided to call fresh elections as soon as possible, drawing condemnation from the ruling Hamas movement.

Also Saturday, Abbas decided to revive the PLO negotiating department, signaling he may pursue peace talks with Israel despite a growing political crisis at home.

The decision, announced by Abbas' office, came just hours after Abbas called for early presidential and legislative elections, in a dramatic challenge to the ruling Islamic militant Hamas movement.

Yasser Abed Rabbo, a member of the PLO executive committee, told Haaretz that the election date would be set within about two weeks.

Saeb Erekat, principal negotiator of the Palestinian Authority, said that the required bureaucratic processes meant that elections could not take place before mid-2007.

Abbas also decided to appoint a new leadership committee for his Fatah Party, in apparent preparations for the elections, his office said.

"I... decided to call for early presidential and parliament elections," Abbas said, after outlining months of failed coalition talks with Hamas. "Let us return to the people, to hear their word, and let them be the judge."

Abbas defends call for elections The PA chairman said that he had the right to fire the Hamas-led government.

"This is a constitutional right. I can do it whenever I want," Abbas said, in a speech broadcast live on Palestine TV, after a week of clashes between his Fatah movement and the ruling Hamas.

"The dismissal of the government is not like [Hamas Foreign Minister] Mahmoud Zahar said, a recipe for civil war. They don't scare us."

"I will look into and have discussed with the Central Election Committee to find the earliest possible way to start preparing for this matter," he added.

In the West Bank city of Nablus, hundreds of supporters of Abbas' Fatah movement rushed into the street in celebration, with dozens of gunmen firing in the air. "Abu Mazen, go, go, we are with you until liberation," the crowd chanted, referring Abbas by his nom de guerre.

In Gaza City, dozens of Fatah loyalists and members of his Presidential Guard gathered outside his residence, firing weapons in the air in celebration and chanting: "We are ready to redeem you with our souls and blood, Abu Mazen."

Abbas said that in the interim period all efforts should be made to form a unity government made up of technocrats, but that Fatah was no longer interested in sharing power with Hamas. "Any government that is formed, Fatah will stay outside," he said.

Speaking about Palestinian Prime Minister Ismail Haniyeh, Abbas said that he respects the premier, whom he called a "noble and honest man," and is willing to have him at the head of a unity government.

"I think today Abu Mazen made history," said Saeb Erekat, a senior Abbas aide. "I think he saved his people from the prospect of civil war... We have a crisis. We have an authority with two heads. So what do we do? Bullets or ballots? Abu Mazen said ballots."

In his address, Abbas blamed the ruling militant group for the spiraling crisis in the Palestinian territories.

He said Hamas had refused to meet international demands to recognize Israel and renounce violence, which had led to crippling Western sanctions and internal political deadlock.

Abbas said that the Palestinians needed a government that could end the international aid boycott.

"Do I need a government for entertainment? I need a government that can lift the siege," he said.

He said a political solution was also needed to resolve the internal Palestinian violence that has raised fears of civil war. "Without a political agreement, security will remain disturbed."

Abbas also rejected claims of a conspiracy to kill Haniyeh, who came Thursday night when re-entering the Gaza Strip at the Rafah crossing. Many Palestinians in Gaza blamed Fatah officials loyal to Abbas for the assassination attempt, in which one of Haniyeh's bodyguards was killed and his son was wounded by gunfire.

Dozens hurt in Hamas-Fatah clashes in Gaza Some 20 people were wounded as Fatah and Hamas supporters traded fire and hurled stones at each other in towns across the Gaza Strip on Saturday after Abbas' calls for elections.

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.

Meshal urges restraint 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."

Trading blame 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.

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.