Cairo ? President Hosni Mubarak refused to step down or leave Egypt and instead handed most of his powers to his vice president Thursday, enraging protesters who warned 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 uprising demanding the president’s resignation. Hours earlier, a council of the military’s top generals announced it had stepped in to secure the country, and a senior commander announced to protesters in Cairo’s Tahrir Square that all their demands would soon be met, raising cries of victory that Mubarak was on his way out.

Several hundred thousand had packed into Tahrir Square, ecstatic with expectation that Mubarak would announce his resignation in his 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, around 2,000 marched on the state television headquarters several blocks away 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 away 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.

Prominent reform advocate and Nobel Peace laureate 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 said. “I call on the Egyptian army to immediately interfere to rescue Egypt. The credibility of the army is on the line.”

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 warned that too many Egyptians are not convinced that the government is serious about making genuine change.

“The Egyptian government must put forward a credible, concrete and unequivocal path toward genuine democracy, and they have not yet seized that opportunity,” Obama said.

Hours before Mubarak’s speech, the military made moves that had all the markings of a coup.

The military’s Supreme Council, headed by Defense Minister 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 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.

But there was no immediate reaction from the military following Mubarak’s speech, and their position remained ambiguous.