By decree, the parliament gave interim presidential authority to the speaker of parliament, Oleksandr Turchynov, himself a leader of the opposition.
But even as demonstrators in Kiev celebrated their victory over the pro-Russian Yanukovych, there were signs of trouble in parts of the Ukraine that still lean more toward Russia than Europe. In the Crimea to the south, men gathered to volunteer for militias to oppose the decrees announced in the capital.
In Kiev, the parliamentarian and former boxing champion Vitali Klitschko urged the thousands of demonstrators in Independence Square to remain where they are in order to protect the advances won by the opposition. Klitschko also said that the "self-defense" militias organized to defend the barricades at the square against riot police should remain on the streets to provide security. "There are no police on the streets right now," Klitschko told reporters. "The police will be reorganized, and we will try to do this as fast as possible."
Another member of parliament warned his colleagues that they needed to move quickly to bring security forces back to work, saying that some of the nation's vital infrastructure, including nuclear power plants, were unguarded.
Maintaining security wasn't the only issue. Turchynov, the new interim president, said Ukraine's pension fund, national currency and banking system were facing "immense problems," according to the news group RIA Novosti.
Russian Finance Minister Anton Siluanov said Moscow would delay a planned purchase of $2 billion in Ukrainian eurobonds until Kiev formed a new government. In December, Russia had signed a deal with President Yanukovych promising a $15 billion support package. The move toward Russian aid, and away from a trade agreement with the European Union, was one of the sparks that began three months of protest in Kiev.
Independence Square was filled with thousands of Ukrainians Sunday who piled heaps of flowers at makeshift shrines beside photographs of some of the 82 protesters who have been killed by riot police in the recent clashes. In western Ukraine, large crowds assembled to mourn the protesters.
Members of the opposition, which now controls Kiev and the central government, also announced that protesters arrested during demonstrations would be freed immediately, while they also sought to detain and prosecute the dismissed prosecutor general, Viktor Pshonka. The interim interior minister, Arsen Avakov, said the new government would open an inquiry into lethal force used by riot police and security forces during the protests.
The whereabouts of Yanukovych remain unknown.
In a single climactic day, the political order of Ukraine was overturned Saturday when the Ukrainian parliament voted to dismiss Yanukovych from office and to free jailed opposition leader Yulia Tymoshenko, who went directly from a prison hospital bed to a stage at Independence Square to address an audience of tens of thousands.
"A day for the history books," tweeted Geoffrey Pyatt, U.S. ambassador to Ukraine.
Still unknown is whether a defiant Yanukovych and a bitterly divided Ukraine will accept any of parliament's decrees. Leaders of the ousted government, especially those from Ukraine's east and south, said they would oppose new measures.
Yanukovych, whose exact whereabouts have been unknown since Friday evening, appeared on television Saturday in a prerecorded interview to say: "I am not planning to leave the country. I am the legitimate president, and I am not going to resign."
"What we witness now resembles Nazi occupation," Yanukovych said. "My car was shot at. But I am not afraid for my life, I am afraid for my country."
Yanukovych said Russian President Vladimir Putin told him that he had spoken with President Barack Obama and promised that "we will negotiate."
But the White House released a statement that praised the "constructive work" done by the Ukrainian parliament and urged "the prompt formation of a broad, technocratic government of national unity."
On Sunday, U.S. national security adviser Susan Rice warned that Russian troop intervention in Ukraine would be a "grave mistake."
"This is not about the U.S. and Russia," Rice said during a wide-ranging interview on NBC's "Meet the Press." "This is about whether the people of Ukraine have the opportunity to fulfill their aspirations and be democratic and be part of Europe, which they choose to be."
William Hague, the British foreign secretary, told the BBC on Sunday: "We don't know, of course, what Russia's next reaction will be."
He noted that Russia had supported a compromise with Yanukovych last week that would have allowed him to stay in power for another 10 months.
"We do know that Russia, as well as the United States, has said a few days ago that they would get behind a deal that had been made, that deal has now been overtaken by events and this is the importance of us continuing a dialogue with Russia," Hague said.
The European Union's foreign-policy chief, Catherine Ashton, is scheduled to come to Kiev on Monday.
Just hours after parliament voted to remove the president on Saturday, his archrival Tymoshenko, a key figure in Ukraine's 2004 Orange Revolution, was released from prison after serving 30 months.
Tymoshenko, suffering from a back injury, was rolled onstage in a pink wheelchair. She gave an emotional, forceful speech, honoring the 82 Ukrainians killed in street fighting and by riot police since Tuesday.
The opposition leader, who still has her trademark blond braid, said that Ukraine would not be truly free until "everyone bears a responsibility for what they have done," a clear reference to the president and his ousted interior minister, who controlled the riot police forces that used live ammunition against protesters. "If we don't prosecute, we should be ashamed."
Tymoshenko, a former prime minister, was sentenced to seven years in prison in a 2011 trial on charges of abuse of power and embezzlement over her role in a deal to purchase natural gas from Russia. Her supporters and many Western countries said the trial and conviction were politically motivated.
In an emergency session, the Ukrainian parliament voted 380 to 0 on Saturday to remove Yanukovych from office, saying he was guilty of gross human rights violations and dereliction of duty. Many of Yanukovych's allies were absent or abstained from voting.
Then the parliament, now dominated by opposition politicians, declared that early presidential elections would be held May 25.
Tymoshenko, who blinked back tears several times, promised: "I am coming back to work. I won't waste a minute to make sure you are happy in your own land."
She ran for president in 2010 but lost to Yanukovych, and most people here assume Tymoshenko will run in the May contest.
"We have been monitoring the situation very closely," said a senior State Department official who spoke on the condition of anonymity because conditions remained so fluid. "What the United States and our European partners have been advocating for consistently this week is a de-escalation of violence, constitutional change, a coalition government and early elections. The developments we are seeing on the ground are . . . moving us closer to those goals."
Russia's Foreign Ministry said in a statement Saturday that the opposition in Ukraine was "pushing new demands, submitting itself to armed extremists and looters whose actions pose a direct threat to the sovereignty and constitutional order of Ukraine," according to Russia's Interfax news agency.
The new speaker of parliament, Turchynov, told his fellow deputies Saturday that Yanukovych had attempted to flee the country.
"He tried to get on a plane that was bound for the Russian Federation but was stopped by border guards. At the moment, he's hiding somewhere in the Donetsk region," Turchynov said, according to Interfax. The Donetsk region, in eastern Ukraine, is home to Yanukovych's Russian-speaking political base.
Tens of thousands of ordinary Ukrainians poured onto the grounds of Yanukovych's abandoned presidential compound, 12 miles from downtown Kiev, to gawk at the manicured lawns, small zoo, golf course, botanical gardens and classic cars.
Museum officials were working with militias to guard the presidential mansion and inventory possessions and works of art they say were probably borrowed or stolen by Yanukovych from state museums and institutions. Journalists and others began to pore over a stack of documents left behind.
"Who knows what he has stashed in there," said Ihor Lihovy, a consultant for the Ukrainian national committee for the preservation of national treasures. "We have been told he hoarded masterpieces. It is a scandal."
Yanukovych built his mansion and its outbuildings after he was elected president in 2010. None of the Ukrainian public or media had seen the inside of the compound before Saturday. An elderly pensioner with a mouth full of metal teeth shouted, "What a thief!" as he took in the marble statuary.
The crowds were orderly and polite. There was no looting, few were allowed to enter the houses or outbuildings, and opposition protesters warned visitors to keep off the grass.
A group of young people, however, found their way into Yanukovych's clubhouse and brought out golf balls and clubs and whacked a few drives down the long fairways.
