CAIRO (AP) -- Egypt's Islamist and secular forces sought to relaunch the street uprising against Egypt's ruling military Friday, packing Cairo's Tahrir Square with tens of thousands of protesters in the biggest rally in months and accusing the generals of manipulating upcoming presidential elections to preserve their power.
But attempts by protest organizers to form a united front against the military were blocked by competing agendas. The protest was riven by distrust and resentments that have grown between Islamists and liberals during the rocky, military-run transition process since the fall of President Hosni Mubarak more than a year ago.
Liberals and leftists accuse the Muslim Brotherhood of abandoning the "revolution" months ago and allying with the military in hopes of securing power. In Friday's rally, many said the Brotherhood was only turning to the streets after the generals proved more powerful in decision-making even after an Islamist-dominated parliament was elected. The liberal groups warned that the Brotherhood could accommodate the military again for a chance to govern.
"The Brotherhood are here for the throne, that's all. We tried them before and they rode the revolution and the blood of martyrs," said Mohammed Abu-Lazeed, an accountant who took part in a march to Tahrir led by communists and socialists.
The Brotherhood said it was protesting to preserve the revolution.
The elections set to begin May 23 were intended to be a landmark in Egypt's transition: the first free choosing of a president after decades of authoritarian rule. After the president is installed, the military is to hand over by the end of June the power it took after Mubarak's ouster.
Instead, political chaos in the lead-up to the vote has fueled fears that the military aims to push a candidate it favors into the presidency to ensure its continued influence and block dramatic reform. This week, the election commission disqualified 10 candidates, including the top three contenders. The move enraged Islamists because among those excluded were the Brotherhood's nominee and a favorite of ultraconservatives known as Salafis.
"Down with military rule," chanted the protesters. Banners by all factions draped around the sprawling downtown plaza demanded that candidates seen as "feloul," or "remnants" from Mubarak's regime be barred from the race -- particularly former foreign minister Amr Moussa, a frontrunner after the disqualifications. Tens of thousands more demonstrated in other cities around the country.
Liberals and youth activists who led last year's anti-Mubarak uprising urged the Brotherhood and other Islamists to agree with them on a single candidate for president who would pursue a "revolutionary" agenda of reform and confront the military.
The Brotherhood, however, refused to step aside in favor of a consensus figure. Though its initial candidate Khairat el-Shater was disqualified, the Brotherhood has a back-up nominee in the race, party leader Mohammed Morsi.
To liberals, its insistence on running fuels the perception that it seeks to monopolize power for itself. And many on the secular side are embittered by events of the past year, when they held anti-military protests only to have the Brotherhood oppose their street action.
"Sell-out, sell-out, sell-out of the revolution," chanted a group of leftists as they marched on the edge of Tahrir, addressing the leader of the Muslim Brotherhood. A group of Brothers in reply shouted, "One hand, one hand," in an attempt to encourage unity.
The majority in Tahrir appeared to be Islamists, though the leftist and liberal camps made their strongest showing in months.
Each group massed around its own stage, blaring slogans and speeches by loudspeaker. A stage of leftist youths blasted hip-hop and revolutionary poetry, while next to it a stage run by the Salafis played verses from Islam's holy book, the Quran, and religious chants. At the Brotherhood's stage, thousands of supporters carried photos of their candidate, Morsi.
In a sign of the competing agendas, many of the Salafis focused on their demand for the reinstatement of their disqualified candidate, Hazem Abu Ismail. A group of his supporters streamed through the crowd carrying a giant banner with his image. Abu Ismail was barred from the race because his late mother held American citizenship, violating rules that a candidate's spouse and parents cannot hold any foreign nationality.
The Brotherhood entered the protest at a time when its frustration has peaked with the military, which has prevented its domination of parliament from translating into real political power. The group won nearly half of parliament in elections late last year. But the generals rejected its demands that the military-appointed Cabinet be removed so it could form its own government. The Brotherhood has also says the military is manipulating the judiciary, the election committee and the writing of a new constitution.
The Brotherhood and other Islamists sought to dominate the constitution-writing assembly, formed by parliament. More than 25 non-Islamists on the body stepped down, protesting it was not diverse enough. A court order later disbanded the assembly.
"Parliament was the first institution Egyptians built and chose," said Taha Shahat, a member of the Brotherhood's political party at Friday's protest in Tahrir. "We want them to have power and the right to carry out decisions."
But the liberal camp was looking for signs that the Brotherhood and other Islamists were willing to compromise in their drive for power.
Enjy Hamadi, with the leftist April 6 youth movement, said the Brotherhood should drop Morsi, agree on a consensus candidate and to a more inclusive assembly to write the constitution. "The Brotherhood needs to return to the revolution with actions, not words," she said.
But Essam el-Erian, deputy head of the Brotherhood's political party, called it "not logical" for Morsi to step aside and denied the group would agree to a constitutional panel that does not include members of the Islamist-dominated parliament.
"We thought that the revolution was on the right path, then were were surprised by attempts to bring back the former regime to power," he said, referring to the military. "This is what forced us to put forth a (presidential) candidate with legitimacy from the street, this is our goal."