Egypt's ruling military announced an overnight curfew around the defence ministry Friday after fierce clashes between troops and anti-military protesters left 59 hurt ahead of landmark presidential polls.

"A curfew has been imposed in the Abbassiya square, around the defence ministry and the surrounding streets," said General Mukhtar al-Mulla, a member of the ruling Supreme Council of the Armed Forces (SCAF), in a television address.

Earlier troops fired into the air to disperse demonstrators.

Military police charged the protesters, chasing them down side streets near the ministry on foot and in military vehicles, firing birdshot and assault rifles into the air amid chaotic scenes, an AFP correspondent reported.

The health ministry said 59 people were hurt.

"During the clashes in Abbassiya, 59 people were injured... of those five are being treated in hospital," said ministry official Ahmed Al-Ansary in a statement.

A military source said the army had chased down protesters "with the help of Abbassiya residents and police forces," arresting 40 people he called "thugs."

The clashes began when some protesters threw rocks at the military police, prompting troops to respond with water cannon and later tear gas.

A blanket of thick smoke engulfed Abbassiya square near the defence ministry, days after deadly clashes there that prompted Friday's demonstration.

Bleeding protesters were ferried away by motorbike and ambulances rushed to the scene, an AFP reporter said. State television showed several soldiers wounded.

Military police, their shields in one hand, picked up rocks and hurled them back at protesters, who used metal sheets from construction sites to protect themselves.

A Belgian photographer with the English-language publication the Egypt Independent was arrested, Egypt Independent reporter Nevine El Shabrawi told AFP.

The Al-Jazeera Misr satellite station reported that soldiers arrested a television crew from the January 25 channel, which is affiliated with the Muslim Brotherhood.

Several thousand secular and Islamist protesters had gathered in Abbassiya, some marching there from Cairo's Tahrir Square, to denounce the ruling military council that took power when Hosni Mubarak was ousted in last year's popular uprising.

The protest comes just three weeks before Egypt's first post-revolt presidential election, after which the ruling military is to hand power to civilian rule.

But protesters say they fear the election will be rigged in favour of a pro-military candidate. Others say they do not trust the SCAF to fully hand power to civilian rule.

"We are here to end SCAF rule. We don't trust them. SCAF is following Mubarak's example, and we want to protect the revolution," said Mohammed Badawi from Ismailiya, a member of the Coalition of Revolution Youth.

Another protester from the Nile Delta city of Mansura, Ahmed Gamal, said he feared the election will be "forged."

"After the revolution, there should be an election committee with integrity. Instead they brought a corrupt one," the 22-year-old told AFP.

Friday's protest comes two days after deadly clashes in the Abbassiya neighbourhood which the health ministry said left at least nine people dead, though field medics say more died.

On Wednesday, unknown attackers stormed a sit-in near the defence ministry by supporters of Salafist politician Hazem Abu Ismail, who was recently disqualified from the presidential race.

Other candidates include former Arab League chief Amr Mussa and Mubarak's last premier Ahmed Shafiq.

The powerful Muslim Brotherhood has fielded the head of its political arm Mohammed Mursi whose main Islamist rival is Abdel Moneim Abul Fotouh, a former Brotherhood member.

Around 2,000 protesters also gathered in central Alexandria on Friday, an AFP photographer said.

On Thursday, the SCAF, which took power when Mubarak was ousted, vowed that the presidential election will be fair and moved to assure the public it will hand over power on schedule.

But it also warned against any threat to the defence ministry.

"We are committed to fair elections 100 percent. We don't have any candidates. All the candidates are respectable Egyptians," said council member Major General Mohammed al-Assar.

"The responsibility, the duty, the law and the right to self-defence, as well as the honour of the military obligates members of the armed forces to defend the defence ministry and its military installations because they are a symbol of military honour and the prestige of the nation," said General Mulla.

"If anyone approaches its (installations), they should hold themselves responsible."

The presidential election is scheduled for May 23 and 24 with a run-off for June 16 and 17 if there is no outright winner.

The military vowed it would transfer power to civilian rule before the end of June, or by May if there is a clear winner in the first round.