Cairo, Egypt (CNN) -- Major Egyptian opposition leader Mohamed ElBaradei warned of potential violent unrest after President Hosni Mubarak announced late Thursday he would not step down before September elections.
Mubarak "is gambling with his country" in order to stay at the helm, ElBaradei told CNN's Wolf Blitzer.
He reiterated the message of his Twitter account, which read, "Egypt will explode. Army must save the country now."
Major clashes between the people and the army, which Egyptians traditionally believe has been on their side, would be devastating, said ElBaradei, a Nobel Peace Prize winner and former director of the International Atomic Energy Agency.
ElBaradei's outlook had changed since hours before, when Egyptians, including thousands packed in Cairo's Tahrir Square, expected Mubarak to step down rather than delegate powers to Vice President Omar Suleiman.
The arrangement failed to mollify opposition leaders or those who have rallied in Tahrir Square for more than two weeks. Another mass protest is planned again Friday after prayer services.
"Mubarak is only one part of this regime," human rights activist Gigi Ibrahim, one of the Tahrir Square protesters, told CNN. "People have been here for 17 days, and they are not for Suleiman, either," Ibrahim said. "Mubarak has lost all legitimacy, and now him handing over the power to the vice president is as illegitimate as Mubarak being in power."
ElBaradei told CNN that Egyptians will not accept the new arrangement.
"Suleiman is considered to be an extension of Mubarak. They are twins. Neither of them is acceptable to the people," he said. "For the sake of their country, they should go."
ElBaradei said a leadership council and a caretaker government should rule the North African nation for one year during a transition to a more democratic process.
Mubarak's defiant remarks about foreign intervention, and his determination to see the transition through, was not what most in the Tahrir Square crowd wanted to hear.
"Get out! Get out!" many chanted as he spoke.
After the speech, parliamentary speaker Ahmed Fathi Srour told state-run Nile TV that Mubarak's move had put the authority for the day-to-day running of the government in Suleiman's hands.
The vice president referred to the past two weeks as the "revolution of the young people."
Suleiman told the protesters to go home and back to work. That had not happened by early Friday.
Yaser Fathi, one of the organizers of a post-speech protest in the northern city of Alexandria, told CNN hundreds of demonstrators marched to an Egyptian military base. They asked the armed forces to intervene and shouted that "the military must step in to get Mubarak out," Fathi said.
Khalid Abdalla, a demonstrator in Tahrir Square and star of the motion picture "The Kite Runner," said early Friday that it's "an incredibly sad moment right now." "Everyone's lost," the actor said. "People are trying to work out what more they can do."
Egyptian journalist, writer and blogger Ethar El-Katatney, appearing on CNN's "Parker Spitzer" Thursday night, likened Mubarak's speech to American television's "Father Knows Best." His earlier speech announcing he would step down in September had gained him some empathy, she said.
El-Katatney said she was worried that Friday could be "bloody" because of the people's frustration.
Nobel laureate Ahmed Zewail, a potential Egyptian presidential candidate, said he sees "several different scenarios" through which a transition could take place.
"The important thing is that the army will protect this transition until a new Constitution is in place," Zewail told CNN before the Mubarak speech. "I am very much appreciative of the fact that armed forces are controlling what's going on."
Freed cyberactivist Wael Ghonim, who emerged as a reluctant hero of Egypt's uprising, had seemed pleased with just the prospect of Mubarak leaving office. He is on leave from his marketing job with the search engine Google in Dubai and was held for 10 days during the protests.
"Revolution 2.0: Mission Accomplished," Ghonim wrote on his Twitter account earlier Thursday, before Mubarak's speech.
CNN's Ivan Watson, Saad Abedine and Arwa Damon contributed to this report.