Two journalists were beaten by Hamas supporters, although neither was seriously hurt. Two other French journalists suffered minor injuries from a small explosion.
Despite a ban on public gatherings, Fatah called the prayer meeting to protest the takeover of the Gaza Strip by Hamas, which seized control of the coastal territory in June. A similar protest a week ago also ended in clashes and harassment of journalists.
Fatah had called its supporters to hold weekly Friday prayers in the open throughout the Gaza Strip to protest what they said was persecution of its members in Hamas-controlled mosques.
After hundreds of Fatah supporters finished prayers in Gaza City, a group of worshipers pelted Hamas-controlled buildings with stones and pipe bombs. Some taunted Hamas officials, including shouts of "Shi'ites," a reference to the group's links to Iran.
Hamas forces began firing into the air to disperse the crowd. In a frenzy, Hamas security forces then began arresting protesters and taking them away in jeeps, chasing them in the streets and also beating several demonstrators.
Associated Press Television News video showed several uniformed Hamas men beating an unarmed protester with long sticks.
A similar protest in Rafah broke up when Hamas men fired in the air. Stun grenades also landed in the crowd, injuring the two children.
A statement from President Mahmoud Abbas's office in Ramallah said the crackdown on protesters "aims to impose a blind dictatorship and an extremist culture that contradicts the values of our people and their heritage."
"The events in the Gaza Strip prove to everyone that the [Hamas] coup is nearing its end. Our heroic people in Gaza will not be terrorized by these mercenaries," the statement said.
Hamas agents in civilian clothes had also joined the uniformed forces in dispersing the protest, beating protesters with sticks.
A small explosion from an unknown source injured two French journalists, but neither was seriously hurt. A Hamas security spokesman said stun grenades and pipe bombs were used by the protesters.
Ihab al-Ghusain, the Hamas security spokesman, said "rioting is unacceptable in the law . . . they had to be contained in any way possible, according to the law."
