CAIRO -- Egypt's Hosni Mubarak refused to step down or leave the country Thursday, and instead handed most of his powers to his vice president, enraging protesters who warned that the country could explode in violence and pleaded for the military to take action to push him out.
The rapidly moving events raised the question of whether a rift had opened between Mubarak and the military command over the spiraling mass uprising demanding that the president go.
Hours earlier, a council of the military's top generals announced that it had stepped in to secure the country, and a senior commander announced to protesters in Tahrir Square that all their demands would be met soon, raising cries of victory that Mubarak was on his way out.
Several hundred thousand had packed the square, ecstatic with expectation that Mubarak would announce his resignation in a nighttime address.
Instead, they watched in shocked silence as he spoke, holding their foreheads in anger and disbelief. Some broke into tears; others waved their shoes in the air in contempt. After the speech, they broke into chants of "Leave, leave, leave."
Organizers called for even larger protests today. After Mubarak's speech, about 2,000 marched on the state television headquarters several blocks from Tahrir, guarded by the military with barbed wire and tanks.
"They are the liars," the crowd shouted, pointing at the building, chanting, "We won't leave, they will leave."
Hundreds more massed outside Mubarak's main administrative palace, Oruba, miles from Tahrir in the
Cairo district of Heliopolis, the first time protesters have marched on it, according to witnesses and TV reports.
The residence where Mubarak normally stays when he is in Cairo is inside the palace, though it was not known if he was there.
Nobel Peace laureate and prominent reform advocate Mohamed ElBaradei, whose supporters were among the organizers of the 17-day-old wave of protests, issued a Tweet warning, "Egypt will explode."
"The army must save the country now," he wrote. "I call on the Egyptian army to immediately interfere to rescue Egypt. The credibility of the army is on the line."
Hours before Mubarak's speech, the military made moves that had all the markings of a coup.
The military's Supreme Council, headed by Field Marshal Hussein Tantawi, announced on state TV that it was in permanent session, a status that it takes only in times of war.
It said it was exploring "what measures and arrangements could be made to safeguard the nation, its achievements and the ambitions of its great people." That suggested that Tantawi and his generals were now in charge of the country.
The statement was labeled "Communique No. 1," language that also suggests a military coup.
Footage on state TV showed Tantawi chairing the council with his chief of state, Gen. Sami Anan, and about two dozen of his top generals, sitting stern-faced around a table.
Mubarak and Vice President Omar Suleiman, a former army general and intelligence chief named to his post after the protests erupted Jan. 25, were not present, the strongest indication during the day of a rift.
There was no immediate reaction from the military following Mubarak's speech, and their position remained ambiguous.
President Barack Obama appeared dismayed by Mubarak's announcement. He said in a statement that it was not clear that an "immediate, meaningful" transition to democracy was taking place, and he warned that too many Egyptians are not convinced that the government is serious about making genuine change.
In his address on state TV, Mubarak showed the strategy he has followed throughout the days of upheaval, trying to defuse the greatest challenge ever to his nearly three-decade authoritarian rule.
So far he has made a series of largely superficial concessions while resolutely sticking to his refusal to step down immediately or allow steps that would undermine the grip of his regime.
Looking frail but speaking in a determined voice, Mubarak spoke as if he were still in charge, saying he was "adamant to continue to shoulder my responsibility to protect the constitution and safeguard the interests of the people."
He vowed that he would remain in the country and said he was addressing the youth in Tahrir as "the president of the republic."
Even after delegating authority to his vice president, Mubarak retains his powers to request constitutional amendments and dissolve parliament or the Cabinet. The constitution allows the president to transfer his other authorities if he is unable to carry out his duties "due to any temporary obstacle."
"I saw fit to delegate the authorities of the president to the vice president, as dictated in the constitution," he said.
Suleiman already was leading the regime's efforts to deal with the crisis, though he has not been able to ease the protests, which have escalated in size and ambition, drawing crowds of up to a quarter-million people.
In the past 48 hours they flared even further out of control, with labor protests erupting around the country and riots breaking out as impoverished Egyptians attacked and set fire to several police and governor headquarters in cities outside Cairo.
Suleiman also has offered dialogue with the protesters and opposition over the nature of reforms. He has not explained how the negotiations fit in if a judges panel, which is led by Mubarak supporters, is recommending amendments.
In any case, the protesters and opposition have refused talks until Mubarak steps down.