Billionaire oligarch Petro Poroshenko is likely to win Ukraine's presidential election on Sunday, but has told CNBC in an exclusive interview that Russia might not accept the results.
"Russia is absolutely unpredictable," Poroshenko replied, when asked if Russia would recognize the outcome of the vote.
Sunday's national election comes at a time of economic and political turmoil in Ukraine, which has been ongoing since pro-Russian president Viktor Yanukovych was overthrown in February. In early March, Russia annexed Crimea in the south of the country and since then, fighting has continued in Ukraine between pro-Russian separatists and Ukrainian forces.
The U.S. and Europe have responded to Russia's aggression towards Ukraine with an escalating series of sanctions. These include visa bans and asset freezes on companies and officials with links to President Vladimir Putin.