Unidentified assailants have descended on Egyptian protesters gathered outside the Defence Ministry in Cairo, triggering clashes that killed at least five people, security officials said.
The violence is the latest episode in more than a year of turmoil in Egypt following the ousting of longtime authoritarian ruler Hosni Mubarak and is likely to fuel more tensions just three weeks ahead of presidential elections.
The military generals who took over from Mubarak in February last year have promised to hand over power to a civilian administration by July 1 but that has not stopped protesters from staging rallies demanding the generals leave immediately.
The security officials said the clashes broke out at dawn when the assailants set upon several hundred protesters who had camped out in the area since early on Saturday to press their demand for the military to go. The protesters fought back and the Health Ministry later confirmed that five people died.
It was not clear if the victims were all protesters or if any of the attackers were among the dead. The ministry said at least 45 people were wounded.
Most of the protesters are supporters of Hazem Salah Abu Ismail, an ultraconservative Islamist who was thrown out of the presidential race because his mother held dual Egyptian-US citizenship, which violates eligibility rules to run in the election.
The officials said rocks, clubs and firebombs were used in the clashes. Witnesses reported hearing gunshots during the fighting, which lasted several hours.
Video footage broadcast on regional television channels showed pitched battles between the two sides on residential streets close to the Defence Ministry in the Cairo district of Abbasiyah.
The rattle of gunshots could be heard in the footage, as well as Abu Ismail supporters chanting "Allahu Akbar," or "God is Great" in Arabic. It was not clear who was shooting. Some of the protesters carried clubs, while many wore hard hats to protect their heads from flying rocks.
The protest camp near the Defence Ministry began on Saturday with only Abu Ismail supporters but they were later joined by die-hards from various pro-democracy groups. The protesters' number would swell to up to two or three thousands in the evenings but stayed at around 1,000 during the days.
There have been unconfirmed media reports that some of the Abu Ismail supporters brought firearms to their encampment after an attack by assailants earlier this week that left one protester dead.
As in earlier attacks on protesters around the Defence Ministry, troops and police deployed in the area did not attempt to intervene.
Since the weekend, Egypt's pro-military state media said the assailants were residents angered by the disruption caused by the protests to life in their neighbourhood. But pro-democracy activists maintain the assailants operate with the blessing of the police or the military, and that they may even be on their payroll.
The latest attack came hours after the protesters outside the Defence Ministry said they had caught an off-duty army officer who came to the area to look around, an act that must have been taken by the generals as an insult to the armed forces.