In a single climactic day, the political order of Ukraine was overturned, more or less peacefully, when the Ukrainian parliament voted Saturday evening to dismiss President Viktor 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.

The parliament plans to quickly name a prime minister and cabinet to act as a caretaker government before elections scheduled for May. Still unknown is whether a defiant Yanukovych and a bitterly divided Ukraine will accept the parliament's decrees. Leaders of the ousted government, especially those from Ukraine's east and south, said they would oppose the new measures.

Just hours after parliament voted to remove the president, his arch rival 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 88 Ukrainians killed in street fighting and by riot police since Tuesday.

The opposition leader, who still has her trademark blond braids, 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."

She told the crowd, "You changed everything — not the politicians, not the diplomats, you changed the world," and called the ousted government "a cancer."

Tymoshenko, a former two-term prime minister, was sentenced to seven years in prison in a 2011 trial charging her with 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 Ukraine 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 on May 25.

Thousands filled Independence Square in the capital, which is still ringed by barricades erected by protesters and "self-defense" militias. The militia members kept order and continued to march in military columns, brandishing home-made metal shields, with wooden clubs and axes over their shoulders.

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 would run in the May contest.

Yanukovych, his exact whereabouts unknown since Friday evening, appeared on television Saturday afternoon in a pre-recorded interview to say, "I am not planning to leave the country. I am the legitimate president and I am not going to resign."

He called the opposition politicians in parliament "bandits," their actions "illegal," and described the protesters as "hooligans."

"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 spoken with President Barack Obama and promised, "we will negotiate," he said.

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."

The statement also applauded Tymoshenko's release from prison, saying "We wish her a speedy recovery as she seeks the appropriate medical treatment that she has long needed and sought." It did not mention Yanukovych.

"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 that the opposition leaders in Ukraine were "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 Interfax news agency.

Ukrainians awoke Saturday morning to rumors and reports that Yanukovych had fled the country, though he is now believed to have returned to his home base in the east of the country.

The new speaker of the parliament, Oleksandr 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 Russia's Interfax news agency. The Donetsk region is eastern Ukraine, which is where Yanukovych's Russian-speaking political base lives.

Police surrendered the center of Kiev to protesters who had commandeered water cannon trucks and personnel carriers from retreating security forces, and claimed full control of the city.

The self-defense militia, composed of hard-core protesters wearing military surplus helmets and mismatched body armor, were enlisted to guard government buildings and direct traffic. The city was peaceful.

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 car collection.

Museum officials were working with militias to guard the presidential mansion and inventory possessions and art works they say were probably borrowed or stolen by Yanukovych from state museums and institutions. Journalists and others also began to pore over a state 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 inside 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, somehow found their way into Yanukovych's clubhouse and brought out golf balls and clubs and whacked a few drives down the long fairways.

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Washington Post staff writer Anne Gearan in Washington contributed to this report.