On Friday, two days before President Mohamed Morsi marks his first year in power, Cairo's Nasr City will host mass rallies to support the president propelled to power last year by Egypt's Muslim Brotherhood.

The Brotherhood's Freedom and Justice Party (FJP) confirmed at a Thursday press conference that it was calling for rallies and an open-ended sit-in on Friday at Cairo's Rabaa Al-Adawiya Mosque, in a show of support for the embattled president and his "democratic legitimacy."

Morsi narrowly defeated Ahmed Shafiq, ousted president Hosni Mubarak's last prime minister, in Egypt's first-ever free presidential polls one year ago.

Friday's rallies will be the second such show of strength by Islamist allies of the president within one week. Last Friday saw hundreds of thousands of Morsi supporters gather at the same location in Cairo to voice support for the president and to 'reject violence.'

The planned demonstrations come as tensions in Egypt reach a fever pitch in anticipation of nationwide protests on Sunday calling for Morsi's ouster.

Opposition groups, spearheaded by the anti-Morsi 'Rebel' signature drive – which claims to have collected 15 million signatures endorsing its call for Morsi to step down – argue that the president has failed to realise revolutionary ideals.

Brotherhood figures, however, backed by relatively hard-line Islamist groups like Al-Gamaa Al-Islamiya, argue that the opposition has failed to respect democratic norms and the results of the ballot box.

Defence Minister Abdel-Fattah El-Sisi on Sunday called for "reconciliation" between the two rival camps, warning that the army would, if necessary, "prevent Egypt from slipping into a dark tunnel of civil unrest and killing, sectarianism and the collapse of state institutions."

The comments prompted speculation about the army's possible return to Egyptian domestic politics.

A three-hour speech by the president on Wednesday night offered some limited concessions and called for national reconciliation, but largely struck a defiant tone.

In his address, the president linked his political adversaries with the former regime, blaming "enemies" for attempting to destabilise the country.

Morsi also played down speculation that the military might support opposition demands for his ouster, stressing that he was the commander-in-chief of Egypt's armed forces.

"The armed forces are deployed in several areas to safeguard the public and defend the nation if need be," the president declared.

As anti-Morsi protesters watching the address from Cairo's Tahrir Square greeted the speech with derision, angry protests were seen in Kafr El-Sheikh and Suez by anti-Morsi demonstrators.

In the Nile Delta's Daqahliya governorate, violent clashes between pro- and anti-Morsi protesters following the speech led to one death, apparently of a Brotherhood supporter, and 243 injuries. Fifty-three people were injured in Sharqiya and two in Gharbiya in similar confrontations.

At the FJP's Thursday press conference, senior party figure Gehad El-Haddad echoed the president's tone, blaming the violence on "thuggery" encouraged by the opposition. He also accused the anti-Morsi 'Rebel' campaign of "joining forces with the former regime."

El-Haddad went on to stress that Friday's Islamist rallies would avoid Tahrir Square, where anti-Morsi protesters have already begun to erect tents in advance of a planned open-ended sit-in.