KYIV, Ukraine -- Yulia Tymoshenko, one of Ukraine's most polarizing political figures, announced Thursday that she will run in the country's May 25 presidential election.
A former prime minister who was released from prison last month following the overthrow of her longtime rival, President Viktor Yanukovych, Tymoshenko said she was running to protect the unity of Ukraine.
Ukraine's presidential election is taking place against the backdrop of Russia's annexation of Crimea, Ukraine's dire economic straits and rumblings of discontent in the country's mainly Russian-speaking eastern provinces.
"I will be the candidate of Ukrainian unity," the 53-year-old Tymoshenko said. "The west and centre of Ukraine has always voted for me, but I was born in the east, in Dnipropetrovsk."
This will be her second attempt to secure the presidency -- she narrowly lost to Yanukovych in 2010.
Once Yanukovych was in power, Tymoshenko was brought to trial and convicted of abuse of office for negotiating a 2009 deal for Russian gas imports at an allegedly excessive price. The trial was widely seen as a political vendetta, but the gas deal and Russian President Vladimir Putin's comments that he found Tymoshenko easy to work with shadowed her image with many Ukrainians.
Tymoshenko struck a hostile stance toward Putin on Thursday, saying she considers him "the No. 1 enemy of Ukraine."
Her return to the forefront of public life brings back one of the most divisive figures in Ukraine's political scene. She is variously admired as an icon of democracy and detested as a self-promoting manipulator with a shady past.
Long before achieving political renown, Tymoshenko was already a high-profile figure in Ukraine. She and her husband took early advantage of former Soviet leader Mikhail Gorbachev's perestroika reforms by creating a popular video rental business.
The couple founded a fuel distribution company and she became head of Unified Energy Systems, a wholesale broker of natural gas. In that post, she became one of Ukraine's richest and most powerful oligarchs -- and was dubbed "The Gas Princess."
With her blond braids and telegenic smile, Tymoshenko came to international prominence in the 2004 Orange Revolution, mass protests that culminated with the overturning of a widely criticized election that had given Yanukovych the presidency.
A re-run of the election handed the presidency to her political ally Viktor Yushchenko, under whom she served as prime minister. However, Yushchenko and Tymoshenko quarreled extensively, leaving the government near-paralyzed at times, and broad voter disappointment helped Yanukovych win the presidency in 2010.
Tymoshenko said Thursday she would not squander voters' trust this time around.
"I will do everything to ensure that our second European revolution does not lead to distrust, depression and disappointment," she said. "I will everyday work to earn the trust that is afforded to me by the people."
Tymoshenko is the best known of an array of potential new candidates in a race left wide open by Ukraine's political upheaval, ranging from former heavyweight boxer Vitali Klitschko to politicians who have their political base in the eastern provinces.
Yet a survey conducted in mid-March by the SOCIS polling organization found Tymoshenko getting only about 12 per cent support among likely voters. The top figure, by a wide margin with 36 per cent, was chocolate magnate and former foreign minister Petro Poroshenko, whom many expect to declare his candidacy before registration concludes on Sunday.
"I am certain that if Poroshenko wins that I, as a person who wants the good of Ukraine, will protect the unity of democratic forces and will support all real reforms and the transformation of our country," Tymoshenko said.
Jim Heintz in Moscow contributed to this story.