CAIRO — A showdown between the Muslim Brotherhood and Egypt’s ruling military council escalated Friday, as the generals chided the group for claiming victory in last weekend’s presidential runoff election and the Islamist candidate pledged defiance.
The dueling challenges were delivered as tens of thousands of Egyptians swarmed into Cairo’s Tahrir Square for a Brotherhood-led protest against attempts by the armed forces to consolidate power. Those moves include a recent constitutional decree giving the military vast authority and enfeebling the future president.

As the crowd swelled, the generals issued a statement defending the decree as in the nation’s “interest” and promising swift and firm action against those who fueled unrest.
Egypt’s presidential election commission had been expected to announce the winner Thursday, but the proclamation was postponed. Mohamed Morsi, the Brotherhood’s candidate, has claimed victory and provided precinct tally reports as evidence. His rival, Ahmed Shafiq, who is widely presumed to be the military’s candidate, has also said he won the election but has not supported his claim with evidence.
Concern grew Friday that the competing claims and the military’s seeming reluctance to transfer power to an elected president could set the stage for a violent confrontation.
The week-long delay in announcing a victor also fueled speculation that the military junta might rig the results after striking a deal with one of the candidates.
“They’re negotiating the winner,” said Shadi Hamid, an Egypt expert at the Brookings Doha Center. “There’s no other explanation I can think of for this long of a delay.”
Friday’s military statement called the announcement of unofficial results by the Brotherhood “unjustified” and “one of the main reasons behind the prevailing division and confusion in the political arena.”
Hours after the statement’s release, Morsi appeared at a news conference with a host of Brotherhood stalwarts, public intellectuals and youth leaders viewed as secular. They said they had set aside differences, if only for the integrity of the electoral process, and would unite to oppose the military’s maneuvers.
But the type of political heavyweights who could have made up a formidable front against the generals were conspicuously absent from the stage. Many have long been wary of the Brotherhood, perceiving it as a group that is quick to cut deals and looks solely after its own interests. Liberal political groups are reluctant to back the Brotherhood because they worry about the prospect of a dogmatic government.
“Even facing the rise of the old regime, the left and the Brotherhood have been unable to form a united front,” Hamid said. “That’s what the military is counting on: divide and conquer.”
In a strident but diplomatically worded speech, Morsi appeared to rebuke the military council for its recent moves and for its warnings against peaceful protests.
“The constitutional declaration clearly implies attempts by the military council to restrict the incoming president,” he said, at times drawing applause from the Egyptian press corps. “This we totally reject.”