The Associated Press - Palestinian gunmen forced a Hamas commander to his knees and fatally shot him early Wednesday outside of the courthouse where he worked as an Islamic judge, escalating factional tensions in the Gaza Strip.

The shooting came two days after the killing of the three young children of a Fatah-allied Palestinian intelligence officer, which sparked fresh conflict between the rival Hamas and Fatah factions. The violence has reduced chances for a unity government and pushed the two sides closer to civil war.

Palestinian security officials said the slain man was Bassam al-Fara, 30, a jurist at the Islamic court and a Hamas commander who belongs to the largest clan in the southern town of Khan Younis.

Witnesses to the shooting said four gunmen calmly ate breakfast at a food stand as they waited for al-Fara outside the courthouse.

When he emerged from a taxi, three of the men grabbed him and forced him onto his knees, while the fourth pulled out a weapon and shot him. The attack left the sidewalk riddled with bullet holes. The witnesses declined to be identified, fearing for their safety.

Dozens gathered at the scene and Palestinian security officers set up roadblocks. Hamas militants set up their own roadblocks throughout town, searching for the shooters.

In a statement faxed to reporters, Hamas openly accused what it called a Fatah "death squad" of the killing.

Fauzi Barhoum, a Hamas spokesman, gave no further details about al-Fara's militant activities but pledged to hunt down the killers.

"This is an ugly crime committed against one of the field commanders of Hamas' military wing and one of the prominent figures in Hamas," Barhoum said. "The fingers that shot him are the same fingers that were involved in the killing of previous Hamas leaders. "Hamas is not going to forget the blood of its members. It is going to pursue and bring those who were involved in today's crime to justice."

Fatah spokesman Tawfik Abu Khoussa rejected the accusations.

"We condemn all acts of anarchy, whatever may be behind them. We call on the brothers in Hamas to stop firing accusations before the investigation," he said.

Palestinian Prime Minister Ismail Haniyeh said from Sudan that he would cut short a foreign trip and return to Gaza.

When Haniyeh left on Nov. 28, he planned to travel for a month. That drew criticism because of the need to conclude negotiations with Fatah on a new government and the political violence raging in the Palestinian territories.

"We need the prime minister to be here now to resolve the internal problems," Haniyeh's political adviser, Ahmed Youssef, said in Gaza on Wednesday.

But Haniyeh dismissed fears of the violence in Gaza escalating to a civil war.

"We want to assure you that words such as 'civil war' don't exist in our dictionary. They don't exist in our makeup, in our culture," Haniyeh told reporters in Khartoum.

Fatah officials, speaking on condition of anonymity because they are not authorized to talk to the press, alleged that al-Fara had been involved in previous attacks against Fatah members.

About 1,000 Fatah loyalists, about half of them uniformed security personnel, marched through Gaza from their headquarters to the residence of moderate President Mahmoud Abbas of Fatah.

National Security Service Maj. Othman Shalouf, 39, said Abbas, known familiarly as Abu Mazen, should act to halt the downward spiral in public order.

"We tell Abu Mazen the time has come to exercise your powers and stop this farce. We are security agencies able to control things and we need a political decision from you," he said.

Some of the protesters fired in the air, but there were no clashes with Hamas militiamen whom they passed on their route. One demonstrator called to the Hamas men through a loudspeaker, appealing for peace.

"We call on you to make today the last day Palestinian blood is shed," he said.

Students of the al-Azhar Islamic university joined the procession, carrying pictures of the three boys killed on Monday, as well as Fatah security men killed in internal clashes.

Fatah and Hamas have been locked in a power struggle since Hamas ousted Fatah in parliamentary elections. More than 40 Gazans have died in battles between the two groups since Hamas took power in March.

Seeking to end the standoff, Abbas has been trying to persuade Hamas to join Fatah in a national unity government. But the talks broke down late last month. Tensions heightened after Abbas announced plans over the weekend to call early elections, drawing Hamas accusations that he is plotting a coup.

Ten radical Palestinian groups based in Syria said Wednesday that they also rejected the proposal for early presidential and legislative elections. The groups, which include Hamas, issued a statement in Damascus saying such polls would "create excessive tension and division" and calling instead for renewed talks to form a government of national unity.

The latest round of violence was sparked by Monday's killing of the three children of Baha Balousheh, an intelligence officer and Fatah loyalist who helped lead a crackdown on Hamas a decade ago. Balousheh, who was not in the car, escaped two previous Hamas assassination attempts.

Hamas denied involvement in Monday's killing.

Large protests broke out in several Palestinian cities in the West Bank and Gaza on Tuesday. Six people were wounded by gunfire, according to hospital officials.