"They were targeting journalists deliberately," said Assad Sawey, who sported a bloodied bandage on his head as he spoke to BBC World television in Cairo.
"They took my camera away and when they arrested me they started beating me up with steel bars...like the ones used here for slaughtering animals," he said.
"They used electric bars to electrify me," he said.
Sawey said that several foreign journalists covering the same demonstration in central Cairo were also arrested: "They were all loaded onto trucks and were removed to somewhere unknown."
It was not clear if these were four French journalists arrested today in the city. They were held for about an hour before being released.
An AFP photographer said Cairo police confiscated his camera's memory card that contained pictures of protestors confronting security forces.
Protests demanding the ouster of President Hosni Mubarak spread across Cairo after Friday prayers, AFP reporters said, as nationwide demonstrations entered their fourth day.