CAIRO - Thugs attacked an anti-military protest near the defence ministry in Cairo on Wednesday and 12 people were killed, officials said, in the politically tense run-up to the first post-uprising presidential election.
The dawn assault sparked fierce clashes between the unidentified attackers and the protesters, who have been there for days calling for an end to military rule, with both sides hurling petrol bombs and rocks, the official said.
The army deployed troops in central Cairo to quell the clashes, a military source told AFP.
A security official said the army and security forces had formed a cordon between the protesters and the attackers, bringing the fighting to a halt.
A doctor at a field hospital set up in the area said 12 people had been killed and dozens injured. A security official confirmed the toll.
The health ministry has so far confirmed nine dead.
Two presidential candidates announced they had temporarily suspend their campaigns over the killings.
The Muslim Brotherhood's Mohammed Mursi told reporters he decided to suspend his campaign for 48 hours "in solidarity with the protesters."
He blamed the Supreme Council of the Armed Forces because it is the ruling authority. SCAF "is the first to be responsible," he said.
His main Islamist rival, Abdel Moneim Abul Fotouh, cancelled all his events for the day over the clashes, a campaign official told AFP.
Leading dissident Mohamed ElBaradei slammed the "massacre" outside the ministry of defence. "SCAF & Government unable to protect civilians or in cahoots with thugs. Egypt going down the drain," the former UN nuclear watchdog chief posted on Twitter.
The protesters, supporters of Salafist politician Hazem Abu Ismail, have been camped out since Saturday after the electoral commission barred the popular hardline Islamist from contesting the upcoming presidential election.
On Sunday, one person was killed and 119 injured in clashes between Abu Ismail supporters and residents of the Abbassiya neighbourhood in Cairo, where the defence ministry is located.
Protests since the popular uprising that toppled president Hosni Mubarak last year have often turned violent, with thugs associated to the previous regime frequently blamed.
The electoral commission on April 14 barred 10 candidates, including the Muslim Brotherhood's Khairat El-Shater and the former president's intelligence chief Omar Suleiman, from standing in the poll to choose Mubarak's successor.
Abu Ismail's nomination was rejected because his mother had taken joint US citizenship, but many of his supporters believe he was the victim of a "plot" by the authorities.
The first round of the presidential election is scheduled for May 23-24, and the SCAF has promised to hand over power to the winner by the end of June.