Just a day after she left the hospital where she was imprisoned, demonstrators outside the Cabinet of Ministers expressed dismay that she could be Ukraine's next president. One of them held a placard depicting Tymoshenko taking power from Yanukovych and reading, "People didn't die for this."
Ukraine is in a delicate state of uncertainty since Yanukovych and protest leaders signed an agreement to end the conflict that left more than 80 people dead last week in Kiev. Soon after signing it, Yanukovych's whereabouts are unclear after he left the capital for his support base in eastern Ukraine. Allies are deserting him.
Russia's next moves in the crisis were not immediately clear, but Washington warned Moscow not to intervene militarily.
The newly emboldened parliament, now dominated by the opposition, struggled to work out who is in charge of the country and its ailing economy. Fears percolated that some regions might try to break away and seek support from neighboring Russia, particularly the Crimean peninsula where Russia's Black Sea naval fleet is based.
Ukraine is deeply divided between eastern regions that are largely pro-Russian and western areas that widely detest Yanukovych and long for closer ties with the European Union.
Yanukovych set off a wave of protests by shelving an agreement with the EU in November, and the movement quickly expanded its grievances to corruption, human rights abuses and calls for Yanukovych's resignation.
The parliament on Sunday assigned presidential powers to its new speaker, Tymoshenko ally Oleksandr Turchinov, who said top priorities include saving the economy and "returning to the path of European integration," according to news agencies. The latter phrase is certain to displease Moscow, which wants Ukraine to be part of a customs union that would rival the EU and bolster Russia's influence. Russia granted Ukraine a $15 billion bailout after Yanukovych backed away from the EU deal.
The Kiev protest camp at the center of the anti-Yanukovych movement filled with more and more dedicated demonstrators Sunday, setting up new tents. Demonstrators posed with an APC and two water cannon that protesters seized during last week's clashes and carried flowers to memorialize the dead, some of whom were killed by snipers.
Tymoshenko, the blond-braided and controversial heroine of the 2004 Orange Revolution, increasingly appears to have the upper hand in the political battle, winning the backing Sunday of a leading Russian lawmaker and congratulations from German Chancellor Angela Merkel and U.S. senators on her release.
Although her spokeswoman, Maria Soroka, said it's too early to discuss whether she will run for president in early elections called for May 25, Tymoshenko is possessed of adamant determination. Even from a wheelchair because of a back problem that was aggravted in 2 1/2 years of imprisonment, she was a powerful speaker Saturday to a crowd of tens of thousands at the protest camp.
"She knows how to do it. She is our hero," said Ludmilla Petrova, one of those at the square the next day.
Other demonstrators objeccted.
"She is just as corrupt as Yanukovych," said 28-year-old Boris Budinok. "We need new faces in Ukrainian politics. The old ones brought us to where we are now."
Tymoshenko's admirers remember her as the most vivid figure of the Orange Rvolution, which forced a rerun of a fraud-riddled presidential election purportedly won by Yanukovych. After the new vote, won by Viktor Yushchenko, Tymoshenko became prime minister.
But she and Yushchenko quarreled intensely and their government was a huge letdown for those who had hoped it would help integrate Ukraine into Europe. Detractors also look askance at her for her years at the helm of Unified Energy Systems, a middleman company that was the main importer of the Russian natural gas on which Ukraine depends. Nicknamed "The Gas Princess," she was accused of giving kickbacks to then-premier Pavlo Lazarenko, who is no imprisoned in the United States for fraud. Later, as deputy prime minister, she pushed through reforms of the energy sector that some said did little more than fill the pockets of her associates.
Susan Rice, President Barack Obama's national security adviser, said he and Russian President Vladimir Putin agreed during a telephone conversation Friday that a political settlement in Kiev should ensure the country's unity and personal freedoms. Rice also said Sunday on NBC's "Meet the Press" that it would be a "grave mistake" for Russia to intervene militarily in Ukraine.