KIEV, Ukraine -- Former heavyweight boxing champion-turned-politician Vitali Klitschko withdrew from Ukraine's presidential race Saturday, throwing his support to a liberal billionaire.
Klitschko, one of three leaders who coordinated recent popular uprisings in the country that unseated pro-Russian President Viktor Yanukovich, announced the decision to withdraw from the scheduled May 25 presidential vote during a convention of his UDAR party in Kiev.
"The only chance to win is through nominating one candidate from united democratic forces," Klitschko said in his convention speech. " ... I propose supporting Petro Poroshenko as a unified presidential candidate from democratic forces."
Poroshenko, 48, is a chocolate and candy magnate with an estimated fortune of about $1.8 billion. The leader of the Solidarnost party, he's held the posts of minister of foreign affairs and economics in different recent governments.
He attended the UDAR convention and thanked Klitschko for his offer.
"In the conditions of war, in the conditions of our state being de facto occupied, in the conditions of deep economic and social crisis, politicians should unite," Poroshenko said in a speech to the UDAR convention. "Up to now, there has never been a precedent in Ukraine politics when two politicians enjoying a high level of popular support would make such a step to unite. We are laying new political traditions."
Poroshenko referred to Russian troops' seizure from Ukraine of the Crimean peninsula, which began at the end of February and was followed by a referendum in the predominantly Russian-speaking region on March 16, in which more that 96% of voters were said to have favored joining Russia.
Russian President Vladimir Putin and the Russian parliament endorsed the action last week, annexing Crimea.
The move has been widely criticized internationally, and the U.S. and the European Union have imposed economic and visa sanctions on a number of Russian politicians who are close to Putin and seen as responsible for the annexation.
The U.N. General Assembly earlier this week voted overwhelmingly to declare the referendum in Crimea was illegitimate.
The situation in Crimea will be a key issue during the Ukrainian presidential campaign, experts said.
"A candidate who will offer a more workable plan of reintegrating Crimea will have the best chances to win," Taras Berezovets, head of Berta Communications, a Kiev-based think tank, said in an interview. "In reality there are only two candidates who will be seriously competing for the presidency -- [former Prime Minister Yulia] Tymoshenko and Poroshenko, and we are most certainly in for a runoff vote too."
An opponent of Yanukovich and a leader of Ukraine's 2004 Orange Revolution, Tymoshenko, 53, served more than 2 1/2 years in jail on corruption charges that were criticized as politically motivated.
She was freed from jail on Feb. 21, the day after violent clashes in Kiev in which dozens of people, mostly opposition demonstrators were killed, many of them by snipers.
She declared her presidential candidacy Thursday, and on Saturday, addressing a congress of her Batkyvshchina party, spoke about the need to keep Ukraine united in the face of a Russian threat.
As the party congress endorsed her presidential nomination, Tymoshenko repeated her earlier slogan that Putin was Ukraine's No. 1 enemy, saying that "Putin united us."
She vowed that Ukraine would get Crimea back but that it needed Western assistance.
"We need to integrate into defense alliances of the Western world," she said in televised remarks. "If we don't do it, we will remain alone facing the aggressor and we will always be weak."
A recent survey conducted by four major Ukrainian polling agencies earlier this week give Poroshenko 29% support and Tymoshenko about 8%.
Klitschko said Saturday that instead of seeking the presidency, he will run to be the next mayor of Kiev.
"I want to make Kiev a really European capital," he said. "All reforms and all initiatives are initiated in the capital city."
The former boxer made a smart move by throwing in the towel at this stage in the race, Berezovets said.
"He would never make into a runoff and the humiliating defeat would be bad for his image as a commencing politician," Berezovets said. "Now Poroshenko and Tymoshenko need to prove to the country who has a better plan to keep its integrity intact and get Crimea back."