Egypt's interim president has moved to calm tensions in the country by proposing new elections in early 2014. Adly Mansour says amendments will be made to the Islamist-inspired constitution and a referendum held on the changes within four months.
The announcement was made as a stand-off continued between the military and supporters of ousted president Mohammed Morsi near the Cairo barracks where at least 51 people were killed during clashes with soldiers on Monday.
The Muslim Brotherhood said its members were fired on at a sit-in for Mr Morsi and has called it a massacre, but police and military say they acted in self-defence after armed men tried to storm the Republican Guard headquarters, throwing stones and petrol bombs.
Adly Mansour says he has ordered an investigation into the deaths, and is urging restraint amid ongoing unrest. He has tried to hold out the prospect of a democratic political future that is attainable - at least in principle - and not too distant, the BBC reports.
His decree issued late on Monday says a panel to amend the constitution, which was suspended last week, would be formed within 15 days. The changes would then be put to a referendum - to be organised within four months. This would lead to parliamentary elections - which could be held early in 2014. Presidential elections would be called once the new parliament convenes.
The Muslim Brotherhood has so far made no public comment on the proposed timetable.
Mr Morsi, an Islamist and Egypt's first freely elected leader, was removed from office by the army last week after mass protests. His supporters accuse the military of staging a coup, but opponents say the move is the continuation of the revolution that deposed President Hosni Mubarak in 2011.
The Muslim Brotherhood's political wing, the Freedom and Justice Party - which took nearly half the seats in historic parliamentary elections held in late 2011 and early 2012 - has urged Egyptians to revolt against "those trying to steal their revolution with tanks".
In a separate development, the grand sheikh of al-Azhar University, Ahmed al-Tayeb - seen as the highest authority in Sunni Islam - warned of civil war and said he was going into seclusion until the violence was over.
The United States has condemned Monday's violence and called for "maximum restraint" after the killings.