Supporters of ousted President Mohammed Morsi protest at the Republican Guard building in Nasr City, Cairo, Egypt, Tuesday, July 9, 2013. He issued a swift timetable late Monday for the process of amending the Islamist-backed constitution and set parliamentary and presidential elections for early 2014. The shootings began during a protest by about 1,000 Islamists outside the Republican Guard headquarters where Morsi, Egypt's first freely elected leader, was detained last week. After a battle lasting about three hours, at least 51 protesters were killed and 435 wounded, most from live ammunition and birdshot, emergency services chief Mohammed Sultan told to the state news agency. At a nationally televised news conference, Army Col. Ahmed Mohammed Ali said police and troops came under "heavy gunfire" at around 4 a.m. and attackers on rooftops opened fire with guns and Molotov cocktails. The Islamist group released the names of 42 people killed outside the Republican Guards' building, as the interior ministry and military said two policemen and a soldier were also killed. Key players in the Egyptian crisis 
 
 Egypt clashes: Divided views The military blamed "terrorists", while witnesses, including Brotherhood supporters at the scene, said security forces fired only warning shots and tear gas, and that "thugs" in civilian clothes carried out the shootings. Mr Erian, deputy chairman of the Brotherhood's political wing, the Freedom and Justice Party (FJP), said the declaration was "a constitutional decree by a man appointed by putchists" which "brings the country back to square one". The group is now torn by pressure from many in its base, furious over what they saw as a "massacre" against Islamists. Five prominent Brotherhood figures have been jailed since Morsi's fall, and Morsi himself is held in detention in an unknown location. Media playback is unsupported on your device Media caption Spokesman for the Egyptian ministry: "There was a treacherous attack" 
 
 In response to the killings 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 military-backed interim president, Adly Mansour, ordered a judicial inquiry into the killings. The changes would then be put to a referendum - to be organised within four months - which would pave the way for parliamentary elections, possibly in early 2014. Adly Mansour's transition timeline Panel formed within 15 days to review constitution 
 
 Constitutional amendments to be finalised and put to referendum in four months 
 
 Parliamentary elections to be held by early 2014 
 
 Presidential elections to be called once new parliament convenes Key players in the Egyptian crisis Is Egypt heading for holy war? According to the Reuters news agency, the Nour party has said it will support Mr Beblawi's appointment, but that it is still studying the nomination of Mr ElBaradei, a former chief nuclear official for the United Nations. Lyse Doucet: The struggle to save Egypt's revolution 
 
 Frank Gardner: Is Egypt heading for holy war? A big Morsi banner remained hoisted in front of the Republican Guards' building.
– Egypt's interim leadership has set an elections timetable to establish a new democratic government, but the Muslim Brotherhood immediately rejected the idea and has called for an "uprising." The interim administration wants the current, suspended draft constitution to be amended and ratified in a referendum; parliamentary elections by 2014; and presidential elections after that, al-Jazeera reports. But here's the response from a senior Muslim Brotherhood official on Facebook: "A constitutional decree by a man appointed by putchists ... brings the country back to square one." And a legal adviser for the Brotherhood's political arm called Adli Mansour's decree "invalid and illegitimate," the BBC reports. The Brotherhood wants nationwide protests today, in the wake of 51 Morsi supporters being shot dead during a Cairo sit-in yesterday, which it is calling a "massacre." The interim administration expressed "deep regret" for yesterday's violence, while the military blamed it on "terrorists." Witnesses say civilian "thugs," not security forces, fired the lethal shots. It's very unclear exactly what happened, reports the AP, which has a more detailed look at the violence. Meanwhile, the Washington Post takes a look at what's at stake for the Brotherhood, which rose from a banned, oppressed organization to a powerful one within a decade, and now must decide whether to fight rather than return to lives of persecution, ousted from the political process.