At least 10 people, mostly journalists, were injured on Friday when police tried to stop clashes between pro-reform demonstrators and government supporters in central Amman.
Police used batons to disperse the clashes outside city hall, beating and injuring nine journalists who were wearing orange vests marked "press," an AFP reporter at the scene witnessed.
The wounded included an AFP photographer and a female Islamist activist.
"We were beaten by police, although we were wearing special press vests," said the photographer. "We thought we would be safe when we stood next to the police and away from the clashes."
A photographer who works for another international news agency said he was ordered by police not to take pictures, while New York Times reporter Kareem Fahim was beaten by 10 policemen.
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Around 2,000 people, including Islamists and youth groups, marched from the nearby Al-Husseini mosque to the city hall before the clashes occurred with hundreds of government supporters.
"Rulers, we want to reform the regime. We want the palace to hear the voices of Jordanians," the demonstrators chanted.
They carried banners reading "We need political, economic and social reforms for future generations," and "It's our right to fight corruption."
It was still unclear if the young demonstrators will defy government warnings and hold an open-ended sit-in.
Meanwhile, rallies for reform and against "rampant corruption" drew hundreds of demonstrators in the southern cities of Tafileh, Man and Karak, as well as Irbid and Jerash in the north.
Since January, Jordan has faced a protest movement demanding political and economic reforms and an end to corruption.