Hamas security forces armed with rifles and clubs beat Fatah supporters trying to hold street prayers to protest the Islamic group's rule in Gaza, witnesses said. Hamas men also assaulted at least seven Palestinian journalists and detained five.

An explosive device thrown into the middle of one protest rally in southern Gaza injured four people.

The prayer protest was the latest episode in friction between the groups since Hamas' bloody seizure of power in Gaza in June. This week Hamas banned all public prayers after Fatah supporters began holding worship sessions that quickly escalated into raucous protests against Hamas rule.

In the northern Gaza refugee camp of Jebaliya, dozens of Hamas security men in uniform and civilian clothes were stationed in the streets to head off any attempt by Fatah supporters to gather. They fired in the air to keep Fatah supporters away, beat several people and detained one man, witnesses said.

Rescue workers said two people were brought to the hospital, one wounded by gunfire and another who had been beaten.

Across Gaza, seven journalists covering the clashes were beaten and two of them were later detained, witnesses and reporters said. Two Associated Press staffers and another news photographer were also briefly detained by Hamas men.

In Jebaliya, a security officer told reporters, "If a single shot is on TV, you know what will happen." He then drew his finger across his throat. At one point a Hamas security man tried to take a photographer's camera.

"I identified myself as a journalist and showed him my card, my journalist card, I told him, 'If you want the tape take the tape, I don't care,' but they kept on beating me and took the camera," Muhammad Abu Sido, a cameraman for a Palestinian news service, told AP Television News.

Similar incidents of harassment against journalists took place during previous weeks' Fatah protests.

Taher Nunu, a Hamas government spokesman in charge of coordinating media coverage, said the reports of harassment of journalists "were individual cases and won't be repeated," and that he was working to free the detained reporters.

Palestinian President Mahmoud Abbas appealed for calm from the West Bank, where he and his Western-backed government have ruled since Hamas took over Gaza.

In the West Bank city of Ramallah, about 750 Fatah supporters gathered with Abbas for prayers to demonstrate solidarity with Fatah in Gaza. Thousand of Palestinians gathered at similar prayer rallies elsewhere in the West Bank.