He said the protesters included lawyers, doctors, engineers and others who have been pressing the king to revise the constitution to hand over more power from the monarchy to the parliament. "This is a march we go on every Friday. We haven't changed our slogans or what we were saying for the past four weeks. Nothing about getting rid of the regime. We;re asking about democratic changes. The 1952 constitution. Fighting corruption. Stop normalization with Israel," Mahadine said.

The attackers were shouting slogans vowing to defend the king with their blood and their souls, he said. "We have no problem with these slogans. This is up to them," he said. "But suddenly they attacked us. They looked just like the thugs we saw in Tahrir in Cairo."

[Updated at 9:26 a.m.: Police said the incident began when government supporters who were conducting their own rally ran into the pro-reform rally and arguments began.

"To the shock of both the marchers and police, the [pro-government] group suddenly charged through the demonstrators and began beating them," the official Petra news agency said.

Taher Adwan, minister of state for media affairs, said the government condemned the attack as a violation of Jordanians' right to demonstrate peacefully. He said the government would investigate the incident to determine who launched the attack "and those behind them."]

-- Kim Murphy in Amman

Photo credit: Amman Net online newspaper