President Hosni Mubarak's face glared down from a giant screen that rippled in the cold breeze above Tahrir Square. His gravelly voice boomed across a multitude of protesters standing silently, standing in shock, but most important, still standing.

When Mubarak stunned them by announcing that he would not quit, jeers filled the air.

When he said he was just like them, the countless thousands who have endured his 30-year rule and battled to bring democracy to Egypt, they laughed.

And long before Mubarak had finished speaking Thursday night, they answered in a roar that rolled across the square like a crashing wave until it drowned out the loudspeakers.

"Erhal! Erhal!" they chanted, thrusting clenched fists in the air. "Leave! Leave!"

They had come to witness history, the triumph of people power over a mighty Arab leader, the only president many of them had ever known.

They had celebrated through a long night of wild rumors: Mubarak had fled to Dubai, United Arab Emirates; Mubarak was in prison; Mubarak was being pushed out by the military.

The euphoria deflated like a popped balloon when Mubarak started speaking at 10:45 p.m. Some gasped out loud. Some began to weep when it became clear that the president would not step down.

The disappointment was palpable. Then so was the anger.

But if the crowd had been operating on false assumptions, it appeared that Mubarak was too. It was clear that the strongman had miscalculated if he hoped to appease his critics by saying he would turn presidential powers over to Vice President Omar Suleiman and that the government would implement a long list of reforms.

"He is making fun of us," said Anas Mohamed, 18, a college student who has joined the protests for the last 18 days. "I'm disgusted."

"He makes us much more angry tonight," said Omar Hesham, 30, an engineer. "It would be better if he said nothing. We had our hopes up and he says nothing new."

"He's ignoring us," said Fatma Ali, 22, fighting back tears. "People have been killed for their freedom here. We have sacrificed everything, and he refuses to sacrifice his office."

Organizers said they would go ahead with a massive protest Friday, the start of the Muslim weekend, with marches in several parts of the city.

"Come back tomorrow," shouted a man atop a burned-out car being used as a barricade. "The fight is just beginning."

As many as 1,000 protesters left the square after the speech to march north along the Nile to the building that houses offices of state television, which has remained fiercely loyal to Mubarak even as other news media have changed their tone.

The army had ringed the building with troops, tanks, heavy machine guns and barbed wire.

Protesters said they would create an encampment similar to the tent city in Tahrir Square.

The protesters' frustration was all the more poignant because of signals just hours earlier that Mubarak would step down. In the afternoon, Gen. Hassan Ruwaini, military commander for Cairo, had gone to Tahrir Square and told protesters, "All your demands will be met today."

So jubilant throngs poured into square all afternoon and into the cold night to savor the moment of victory and enjoy the first sweet taste of freedom. If there weren't a million people, it felt like there were.

Families hugged and wept, boys waved flags from atop statues and lampposts, and laughing men sang insulting songs about a tyrant who they thought was history.

Men whirled round in frenzied dances, or snaked through the crowd, banging on tambourines and cymbals, faces beaming in delight.

Movie stars, television hosts and sports celebrities laughed with their fans. Children ran underfoot while families rested in makeshift Bedouin-style tents lined with thick carpets.

Khaled ElShazly, 42, a lawyer, brought his wife and four children, ages 7 months to 12 years, to hear Mubarak announce his resignation. ElShazly wore his black legal robes, and his oldest son, Ahmad, wore an Egyptian flag like a cape. His wife wore the full facial covering used by some Muslim women.

"I want my family to remember this forever," he said happily. "It's rare to make history. But this is truly history."

What if Mubarak didn't resign, he was asked. He frowned, and said, "We will stay until all our demands are met. Or we will all become martyrs."

Off on the side, protest leaders worked their cellphones in search of reliable news, and warned that they would not accept military rule, or a transition headed by a Mubarak aide.

"We want a civilian democracy, not a military rule," said Zyad Eleaimy, one of the protest organizers.

Moaz Malek said he couldn't find the words for how he felt. At 26 years old, he already has been jailed twice by Mubarak's regime. His father, industrialist Hasan Malek, has been a political prisoner for seven years.

"It is time for Egypt to be free," he said. "We need elections. We need democracy."