Clashes between protesters and unknown assailants outside Cairo's defence ministry, which have left at least nine dead since early Wednesday morning, have been condemned by politicians from across the political spectrum.

The clashes began at dawn when plain clothed men attacked protesters who were camping outside the defence ministry in Abbasiya, Cairo, to protest against military rule.

The Muslim Brotherhood's official website, Ikhwanonline, announced that the group would suspend campaigning in support of its presidential candidate, Mohamed Morsi, for two days in protest at the clashes.

Egyptian political figure Mohamed ElBaradei has blasted the army on Twitter, writing, "Massacre in front of the Ministry of Defence (MOD) and [the] government unable to protect civilians or in cahoots with thugs. Egypt is going down the drain."

ElBaradei urged the ruling military council and the El-Ganzouri government to step down because "Egypt is dying in your hands."

ElBaradei had intended to stand for president but decided to quit the race because he was unhappy at how the military council was administering the transitional period. He has recently established the liberal Constitution Party, which he says will represent all Egyptians.

Presidential candidate Hamdeen Sabbahi of the El-Karama Party used Twitter to defend the right of Egyptians to protest peacefully.

"We will not accept the spilling of blood and denying them the right to hold peaceful protests and we will protect our youth," Sabbahi said.

Former presidential hopeful Ayman Nour, who was ousted from the race due to a previous criminal conviction, urged Egyptians "to show solidarity with the martyrs."

Abdel-Moneim Abul-Fotouh, one of the frontrunners in the presidential race, has announced that he will also suspend his campaign to protest the violence.

"The state has to protect peaceful protests. It is not the citizen's duty to fight attempts to disperse sit-ins," Abul-Fotouh said. "Parliament has to wake the interior minister so he can do his job."

The April 6 Movement – which lost one of its members, Ibrahim Abul-Hassan, in the violence – said that his last words on Facebook were eerily prescient: "I will write a new future for my country with my own blood."

The movement's spokesperson Enjy Hamdy said it would to continue with the revolution regardless of how many of its members fall.

"No matter how many of our youth are detained, injured, or martyred, our revolution will continue until it fulfils all of its goals," Hamdy said. "And history will be a witness to all these massacres which were committed by the military council and General El-Roweiny, just as it will witness the crimes of Mubarak. And all of you should know that your place will be in the garbage bin of history and in prison."

The "We are All Khaled Said" revolutionary Facebook page which has been publishing a constant flow of photos and video footage from the Abbasiya clashes, has dubbed the unknown assailants who attacked the protesters as "criminals."

"Anyone who took part in murdering an Egyptian is a criminal…anyone who raised a weapons against his Egyptian brother is a criminal…the Egyptian blood is sacred…weapons are not a means to resolve problems," the group said.

The Salafist Nour Party has also appealed for all honourable people to end the bloodshed.

"What is happening now is a massacre and we cannot remain silent about it," the party wrote on its official Facebook page. "We call on all people of honour…stop the spilling of Egyptian blood."

Emad Abdel-Ghafour, the head of the Nour Party, has joined the protesters in Abbasiya to show solidarity with those killed.

The Islamist Wasat Party has also expressed its outrage at what is happening near the defence ministry, including the murder and ruthless beating of peaceful protesters at the hands of the so-called "third party," which the military council says is behind all recent violence.

The party has asked parliament to hold an emergency session and take a strong decision to recover the lost rights of Egyptians, especially their freedom to protest and express their opinion.