New Bloodshed in Egypt as Islamists Defy Threat of Force CAIRO - Dozens of people were reportedly killed in renewed clashes on Friday as thousands of followers of the embattled Muslim Brotherhood took to the streets of Cairo and other cities, facing police officers authorized to use lethal force if threatened. As the Islamist Brotherhood sought to regain momentum after a crushing crackdown by security forces on Wednesday in which almost 640 people were killed, witnesses spoke of gunfire whistling over a main overpass in Cairo and at a downtown square as clashes erupted and police officers lobbed tear gas canisters. Reports of a rising death toll continued throughout the day, with up to 50 dead, said a Reuters report that quoted security officials. About 30 bodies were laid out in a mosque in Ramses Square, which was being used as a makeshift field hospital as the injured were brought in from clashes that included gunfire nearby. Fatalities were also reported from protests in other parts of Cairo and in the city of Ismailia near the Suez Canal, and fighting erupted in Fayoum and Alexandria. In some of the urban battles, it was not immediately clear who was fighting, as gunmen in civilian clothes opened fire. Under military lockdown after the authorities declared a state of emergency, Cairo and other cities had been bracing for more violence after Friday Prayer, which has been a central trigger for protest since the wave of turmoil known as the Arab Spring swept through the Arab world beginning in early 2011. In response to the call for what the Brotherhood called a "Friday of rage," thousands of supporters of the deposed president, Mohamed Morsi, marched from northeast Cairo after the noon prayer, witnesses said, defying a show of strength from the military as they headed toward Ramses Square downtown. For its part, the army and security forces sealed off streets and positioned armored vehicles in Tahrir Square, once the crucible of broad revolt but now a stronghold of Morsi opponents. Some of the violence had ebbed by nightfall and a curfew came into effect, but a spokesman for the Muslim Brotherhood, Gehad el-Haddad, said in a Twitter message that the day marked the first of what would be daily rallies across Egypt. The outcome of the growing confrontation between secular and Islamist forces in Egypt - a contest that could shape the country and the region for years to come - seemed cloaked in uncertainty. "After the blows and arrests and killings that we are facing, emotions are too high to be guided by anyone," Mr. Haddad said, according to Reuters. The clash of powerful forces has alarmed many outsiders stunned by the ferocity of the crackdown and fearful of the potential regional repercussions. On Friday, news reports from Paris said President François Hollande consulted Britain and Germany about the crisis, but it was not immediately clear how the situation could be swayed by outsiders" diplomacy. On Thursday, some European officials called for a suspension of aid by the European Union, and at least one member state, Denmark, cut off support. The British and French summoned the Egyptian ambassadors in their countries to condemnthe violence. The Brotherhood, for decades the repository of Islamist sentiment, said it wanted millions to march on Friday to display "the pain and sorrow over the loss of our martyrs." In a statement, the Brotherhood said the actions of the military-backed interim government against Mr. Morsi's supporters had "increased our determination to end them." With their leaders jailed or silent, however, some Islamists reeled in shock at the killings, which began on Wednesday when security forces razed two protest camps where Mr. Morsi's supporters had been staging sit-ins since his ouster six weeks ago. By Thursday night, health officials had counted 638 dead and nearly 4,000 injured, but the final toll was expected to rise further, in the worst mass killing in Egypt's modern history. David D. Kirkpatrick reported from Cairo, and Alan Cowell from London. Mayy El Sheikh and Kareem Fahim contributed reporting from Cairo, and Christine Hauser from New York.