Petro Poroshenko, independent member of the Ukrainian Parliament, delivers a speech during a convention of Ukraine's UDAR Party in Kiev on March 29, 2014. Boxer turned opposition leader Vitali Klitschko dropped out of Ukraine's snap presidential polls to help the candidacy of Poroshenko, a charismatic tycoon who made a fortune selling chocolates and backs closer Western ties. The towering sports star's decision leaves the crisis-hit nation of 46 million with two clear frontrunners in the May 25 vote -- business baron Petro Poroshenko and the highly divisive and corruption-stained opposition leader Yulia Tymoshenko. Klitschko added that he planned to run for mayor of Kiev in elections that will be held alongside the presidential polls. AFP PHOTO/ANATOLIY STEPANOV

Petro Poroshenko (L), independent member of Ukrainian Parliament and boxer turned opposition leader Vitaly Klitschko (R) shake hands after convention of Ukraine's UDAR Party in Kiev on March 29, 2014. Boxer turned opposition leader Vitali Klitschko today dropped out of Ukraine's snap presidential polls scheduled on May 25 to help the candidacy of a charismatic tycoon Petro Poroshenko who made a fortune selling chocolates and backs closer Western ties.Instead, Klitschko plans to run for mayor of Kiev in elections that will be held alongside the presidential elections. AFP PHOTO/ANATOLIY STEPANOV

Petro Poroshenko (L), independent member of Ukrainian Parliament and boxer turned opposition leader Vitaly Klitschko (R) give a press conference after a convention of Ukraine's UDAR Party in Kiev on March 29, 2014. Boxer turned opposition leader Vitali Klitschko today dropped out of Ukraine's snap presidential polls scheduled on May 25 to help the candidacy of a charismatic tycoon Petro Poroshenko who made a fortune selling chocolates and backs closer Western ties.Instead, Klitschko plans to run for mayor of Kiev in elections that will be held alongside the presidential elections. AFP PHOTO/ANATOLIY STEPANOV

Petro Poroshenko, independent member of Ukrainian parliament files his documents to register as a candidate for the upcoming presidential elections at the Central Electional Commission in Kiev on March 29, 2014. Boxer turned opposition leader Vitali Klitschko today dropped out of Ukraine's snap presidential polls scheduled on May 25 to help the candidacy of a charismatic tycoon Petro Poroshenko who made a fortune selling chocolates and backs closer Western ties. Instead, Klitschko plans to run for mayor of Kiev in elections that will be held alongside the presidential elections. AFP PHOTO / VOLODYMYR SHUVAYEV

Petro Poroshenko, independent member of Ukrainian parliament, speaks to the press after filing his documents to register as a candidate for the upcoming presidential elections at the Central Electional Commission in Kiev on March 29, 2014. Boxer turned opposition leader Vitali Klitschko today dropped out of Ukraine's snap presidential polls scheduled on May 25 to help the candidacy of a charismatic tycoon Petro Poroshenko who made a fortune selling chocolates and backs closer Western ties. Instead, Klitschko plans to run for mayor of Kiev in elections that will be held alongside the presidential elections. AFP PHOTO / VOLODYMYR SHUVAYEV

Ukranian politician Petro Poroshenko talks to members of the media after meetings with British parliamentarians in central London, Wednesday, March 26, 2014. (AP Photo/Lefteris Pitarakis)

Ukrainian politician Petro Poroshenko talks to members of the media after meetings with British parliamentarians in central London, Wednesday, March 26, 2014. (AP Photo/Lefteris Pitarakis)

Ukrainian politician Petro Poroshenko poses for photographers after meetings with British parliamentarians in central London, Wednesday, March 26, 2014. (AP Photo/Lefteris Pitarakis)

Ukrainian politician Petro Poroshenko poses for photographers after meetings with British parliamentarians in central London, Wednesday, March 26, 2014. (AP Photo/Lefteris Pitarakis)

Ukrainian politician Petro Poroshenko gestures as he jokes about the weather as he poses for photographers after meetings with British parliamentarians in central London, Wednesday, March 26, 2014. (AP Photo/Lefteris Pitarakis)

From left, Ukrainian parliamentarians Vitali Klitschko, leader of the UDAR (Ukrainian Democratic Alliance for Reform) party, Petro Poroshenko, and Andriy Shevchenko, Fatherland party, pose for the media outside 10 Downing Street for a meeting with British Prime Minister David Cameron and Foreign Secretary William Hague, London, Wednesday, March 26, 2014. (AP Photo/Sang Tan)

(FILES) -- This March 7, 2014 file photo shows then Ukrainian member of parliament and businessman Petro Poroshenko speaking to journalists after a meeting at the Elysee presidential palace in Paris. Ukrainian presidential contender Petro Poroshenko, seen as polls favorite for the May 25, 2014 presidential election, made his candidacy official on March 28, 2014. AFP PHOTO / ALAIN JOCARD

(FILES) -- This March 7, 2014 file photo shows Ukrainian member of parliament and businessman Petro Poroshenko speaking during meeting in Paris. Ukrainian presidential contender Petro Poroshenko, seen as polls favorite for the May 25, 2014 presidential election, made his candidacy official on March 28, 2014. AFP PHOTO / KENZO TRIBOUILLARD

Former Security and Defence Council Petro Poroshenko is seen in this Sept. 22, 2005 photo in Kiev, Ukraine. Prosecutors have accused President Viktor Yushchenko's close ally Porosenko of abuse of power on Monday Oct 10 2005.

The head of Ukraine's Defense and Security Council, Petro Poroshenko, speaks to the media in Kiev, Ukraine, Thursday, Sept. 8, 2005, Poroshenko announced his resignation as President Viktor Yushchenko's coalition government faced the biggest crisis of its seven-month existence. (AP Photo/Efrem Lukatsky)