Egypt's interim president Adly Mansour
Egypt's interim president Adly MansourReuters

Egypt on Sunday announced early presidential elections likely to anoint the general who overthrew Islamist president Mohammed Morsi.

AFP reported that the country’s interim president Adly Mansour announced the elections in a televised address, a day after 49 people died in clashes between Islamist protesters and police and thousands rallied in support of military chief General Abdel Fattah al-Sisi.

Sisi was expected to declare his candidacy for the election, scheduled before mid-April, after a show of support including Saturday's large rally in Cairo's Tahrir Square.

The weekend clashes and bombings also highlighted the interim government's precarious grip seven months after Morsi's overthrow.

On Sunday, an Al-Qaeda inspired group released a video it said showed its fighters downing with a missile a military helicopter in the lawless Sinai peninsula.

The group, Ansar Bayt al-Maqdis, also claimed credit for a car bombing outside police headquarters in Cairo on Friday morning that killed four people.

The military has acknowledged five soldiers were killed in an incident involving a helicopter on Saturday, but said it was "an accident," according to AFP.

Over Friday and Saturday, five bombs went off after the attack on the Cairo police headquarters, killing to more people.

The violence came as Egypt commemorated the 2011 uprising that overthrew former president Hosni Mubarak, leading to three years of tumult that many hope Sisi's election will end.

As Mansour addressed the nation to announce the early presidential election, relatives of those killed on Saturday assembled outside a Cairo morgue, chanting anti-military slogans.

In his address, Mansour, a judge the military appointed as interim president to replace Morsi, pledged to "uproot (terrorists) and show them no mercy".

The government says a series of polls that started with a constitutional referendum in January and will end in parliamentary elections will restore an elected government by 2015.

Sisi took the approval of the constitution earlier this month as a vote of confidence for his presidential bid.

A parliamentary election had been scheduled ahead of the presidential poll, but Mansour said Sunday he had revised the timetable following many demands.

Sisi, accused by Morsi supporters of carrying out a coup ending the Islamist's single year in power, still faces a determined opposition and a semi-insurgency.

Hours before Mansour spoke, terrorists ambushed a bus carrying soldiers in the restive Sinai Peninsula, killing four, according to AFP.

The army vowed in a statement to "eliminate those belonging to the Muslim Brotherhood who call for darkness and dissension and excommunication".

The interim government declared the Muslim Brotherhood a terror organization, sparking new tensions between the military and the Brotherhood's supporters.

The terror designation came a day after a massive suicide car bombing in the Nile Delta city of Mansoura killed 16 people and wounded more than 100. While Ansar Bayt al-Maqdis claimed responsibility for the attack, the interim government says there is a connection between the Muslim Brotherhood and the ongoing terrorist attacks in Egypt.