Hundreds of people were injured in clashes with security in and around Cairo's Tahrir Square on Wednesday in one of the biggest protests seen in Egypt since the ouster of Hosny Mubarak.
Thousands of people took to the streets of the capital to demand justice for those killed in the January 25 uprising, which led to the fall of the former president, dpa reported.
Egypt's Ministry of Health said that of the more than 600 injured since clashes first erupted late on Tuesday, at least 515 required hospital treatment. Others were treated on-site.
"I just want to know if he's dead or alive," said 31-year-old Sayid el-Rimawi, who came to Tahrir Square from the poor governorate of Kafr Sheikh holding a photo of his 19 year-old brother, who he says went missing on January 25th.
"If he's in prison, I just want to see him, bring him food. If he's in a hospital, I can see him," he said. "If he's dead give me his body to bury. All I ask is to know."
Security forces used tear gas, rocks and batons in their attempt to disperse protesters.
Pictures posted by activists online showed injuries allegedly inflicted by rubber bullets fired by security forces.
Protesters chanted, "The people demand the fall of the army chief."
In Egypt, criticism of the military, in charge of the country since the departure of Mubarak, remains taboo.
The military backed the January 25th revolt against Mubarak and still enjoys the support of many Egyptians.
But people are asking why, five months on, Mubarak and his top aides have yet to be brought to justice, particularly since military courts have been swift in trying civilians.
The army says up to 7,000 civilians have been tried in military courts since it assumed power, but rights groups say the number is closer to 10,000.
Meanwhile, others spoke out against the protest.
"These are a bunch of unemployed thugs just here to create chaos. These are hooligans, you think they are part of the revolution?" one man said.
Many shops in the area remained closed, and several roads and pavements were reduced to rubble after the fighting.
Tension began brewing on Sunday, when a court delayed the start of a criminal trial for former Interior Minister Habib al-Adly, who served as head of Egypt's security services for nearly 20 years. He is being charged with ordering lethal forces against protesters during the uprising.
The demonstrators are demanding faster and more transparent trials of officials responsible for the deaths of the more than 800 protesters killed during the 18 days of uprising.
"It has been four months since the revolution, and nothing has changed! They are still attacking us in the same ways," said Ahmed Youssef, a 26-year-old graduate student in Tahrir Square.
A major protest had already been planned weeks ago for this Friday to demand speedy trials.