Gunfire killed at least six people on Monday at a Fatah rally attended by hundreds of thousands in central Gaza commemorating the late Palestinian leader Yasser Arafat, the Palestinian TV reported.
Eyewitnesses said the shooting started as forces loyal to the Gaza Strip's Hamas rulers opened fire on Fatah followers.
Fatah officials accused Hamas forces of opening fire from the nearby Islamic University. Hamas said its men came under fire from Fatah gunmen and shot back. Later, Hamas said the victims were killed by Fatah gunmen who had fired from rooftops.
Ehab Ghussen, spokesman for the Hamas-controlled Interior Ministry said: "Fatah is responsible for continued incitement against the Palestinian police, and there was a clear attempt to bring back chaos."
According to Reuters, many Fatah supporters fled in panic after the gunfire erupted. At least 85 people were wounded, medical officials said.
The office of Palestinian President Mahmoud Abbas, who leads the Fatah government out of the West Bank, denounced Hamas' actions as a "heinous crime."
The rally had been expected to be Fatah's biggest show of strength since Hamas took control on the Gaza Strip in June, expelling the security forces of Fatah. However, Hamas erected at least 10 checkpoints on Gaza Strip's main north-south road to inspect vehicles heading to the event, local residents said. Fatah officials said some buses were turned back and passengers then set out on foot, but Hamas denied this.
WAFA news agency accused Hamas of stealing dozens of pictures of Arafat and 30,000 headdresses symbolizing the late leader.
A pro-Hamas Internet site quoted a Hamas security official as saying trucks carrying yellow Fatah flags and hats were seized "at a time when the Gaza Strip is being deprived of basic goods and medicine".
