Egypt's top military council has given army chief Field Marshal Abdel Fattah al-Sisi a green light to run for president.

A security source said: "The top army officials all okayed Sisi running for the presidency".

The newly promoted army chief is expected to announce his candidacy within days.

He has calculated that he can win the votes of those who backed Mohammed Mursi for president in 2012 simply because he represented change from the era of Hosni Mubarak, who was ousted in the revolutions that swept the Arab world.

But despite his present popularity, Field Marshal Sisi has no record as a democrat and has shown himself willing to use deadly force against those who disagree with him.

He has trodden a careful path to power since overthrowing Mr Mursi, Egypt's first freely elected president, last July.

It is the kind of measured advance he has made all his life, from his childhood in the dirt lanes of Cairo's Gamaliya district, to the highest rank in one of the largest armies in the Middle East.

The world knew little of the Field Marshal before he appeared on television on 3 July and announced the removal of Mr Mursi after mass protests against the Islamist leader.

It was Mr Mursi who appointed then General Sisi as army chief of staff and defence minister in August 2012.

Mr Mursi, a Muslim Brotherhood leader, wanted a young general to reduce the influence of the military old guard who had served under Mr Mubarak before the 2011 revolution.

His reputation for being a pious Muslim may have also appealed to Mr Mursi.

But while Mr Mursi appeared deaf to criticism, Field Marshal Sisi was tuned in to the rising discontent on the streets over the brotherhood's mismanagement.

Eventually, he issued an ultimatum to the man who appointed him: Bow to the demands of protesters within 48 hours or the military will act.

Meanwhile, Egypt's Deputy Prime Minister Ziad Bahaa El-Din has tendered his resignation to Prime Minister Hazem el-Beblawi.

He also held the post of minister of international cooperation in Egypt's army-backed interim government.