President Obama issued a stern written statement following Egyptian President Hosni Mubarak's decision to transfer many of his powers to his vice president, Omar Suleiman, but not step down, a move that enraged crowds gathered in Tahrir Square.
"The Egyptian people have been told that there was a transition of authority, but it is not yet clear that this transition is immediate, meaningful or sufficient," said President Obama in the statement. "The Egyptian government must put forward a credible, concrete and unequivocal path toward genuine democracy, and they have not yet seized that opportunity."
Obama also pushed the Egyptian leadership to be clearer about its intentions and how it will address the demands of the Egyptian people.
"We therefore urge the Egyptian government to move swiftly to explain the changes that have been made, and to spell out in clear and unambiguous language the step-by-step process that will lead to democracy and the representative government that the Egyptian people seek. ... There must be restraint by all parties. Violence must be forsaken. It is imperative that the government not respond to the aspirations of their people with repression or brutality. The voices of the Egyptian people must be heard."
A crowd of hundreds of thousands of people gathered in Tahrir Square expecting to hear Mubarak say he was leaving office went silent as Mubarak appeared on television. But towards the end of the speech, when it became evident that the president wasn't resigning, the crowd erupted into a roar and began angrily chanting, "Leave now, leave now, leave now."
Thousands of protesters were planning to take to the streets once again on Friday to continue calling for Mubarak's ouster.
Shortly after Mubarak spoke, the supreme commander of the army sent a text message that went to nearly every cell phone in Egypt saying the military would have an important statement later tonight.
Suleiman, also speaking to the nation, told the country's youth to go home and to not listen to satellite television. But the mood among protesters was hardly that of retreat. Instead, angry crowds marched towards the Egyptian state TV building in downtown Cairo.
Mubarak's speech was defiant, but he also announced the formation of a committee that will study amendments to the Constitution, and said discussions were being held to lift the emergency law -- one of the main U.S. demands -- but only when the security situation permits.
Egypt's controversial emergency laws have been in place since 1967 and give the government far-reaching powers at the expense of judicial review and civil liberties.
In an address directed to the youth of Egypt, Mubarak said he was pained by the deaths that have occurred since protests began on Jan. 25.
"The blood of the martyrs and the injured will not go in vain," he said. "I will not hesitate to fiercely punish those who are responsible. I will hold those in charge who have violated the rights of our youth with the harshest punishment stipulated in the law."
The United Nations and Human Rights Watch estimates that 300 people have been killed in Egypt's protests.
The 82-year-old president appeared to rebuff the Obama administration's urgings that Mubarak heed protesters' demands, saying several times he won't "listen to any foreign interventions or dictations."
Jubilation in Tahrir Square Turns to Anger
There were conflicting reports during the day about whether Mubarak, who has ruled for 30 years, would resign. Earlier today, an Egyptian army general waded into the jubilant crowd of protesters in Cairo's Tahrir Square today and told them cryptically, "All your demands will be met tonight," leading the crowd to erupt into a roar of cheers.
When asked by ABC News whether that meant that Mubarak would leave office, Army Gen. Hassan al-Roueini only said, "It ends tonight."
Thousands of people streamed into the square in anticipation of witnessing history. Crowds say the national anthem, a sea of Egyptian flags waved and youths climbed upon light poles. Camera flashes sparkled through the crowd as demonstrators tried to capture what they expected to be a moment in history.
But the jubilation and celebration was quickly reduced to sullen anger and slumped shoulders.
In the United States, administration officials watched the crowd and later Mubarak's speech with apprehension. In brief remarks before Mubarak's speech, President Obama hailed the young people as a new generation "who want their voices to be heard."
"What is absolutely clear is that we are witnessing history unfold. It is a moment of transformation that is taking place because the people of Egypt are calling for change," Obama said.
Egypt's armed forces issued a statement broadcast earlier today on state radio, saying they will protect the people and will support the demands of the people. The state television reported that the council of armed forces met today to discuss the current situation, and resolved to convene regularly.
"We will ensure the protection of the people and that their legitimate demands are met," the army said.
Neither Mubarak nor Suleiman were present at the meeting.
The protests, in its 17th day, appeared to gain momentum early in the day as protesters and labor unions across the country went on strike today, adding more fuel to the revolutionary fire.
Factory workers, textile workers, laborers on the Suez Canal all stopped working. On Tahrir Square, doctors and bus drivers joined the protests today, in a sign of solidarity. The transport strike brought traffic in a city famous for its congestion, to a standstill.
Mubarak Doesn't Resign, Angering Protesters
Tanks surrounded key government buildings and federal employees were advised to stay at home.
In a move to appease protesters, the state prosecutor launched a corruption investigation against three former government ministers and a steel tycoon turned parliament member who was a key figure in Mubarak's ruling party, according to Egyptian state TV.
The embattled Egyptian government also announced the formation of a "fact-finding committee" on the "youth uprising" and that will investigate the "unfortunate events" that took place in Tahrir Square on Feb. 2, the day the square turned into a battleground between protesters and pro-Mubarak supporters. The government, however, didn't make it clear if they are investigating people on camel-backs who stormed the square, the protesters, or both.
ABC News' Andrew Morse, Jon Garcia, Aaron Katersky, Sunlen Miller and Ann Compton contributed to this report