President: Petro Poroshenko
Petro Poroshenko won the presidential election of May 2014 at a time of crisis which saw the ouster of his predecessor, the loss of the region of Crimea to Russia and a separatist rebellion in the east of the country.
The vote was seen as a critical step toward resolving Ukraine's protracted turmoil.
Mr Poroshenko, a billionaire chocolate factory owner, won an unprecedented first round victory in the elections which were held three months after pro-Russian President Viktor Yanukovych was chased from office by crowds following months of street protests.
Russia said it was ready to talk to Mr Poroshenko, raising hopes of an easing of tensions between Kiev and Moscow.
And Mr Poroshenko said he wanted to sign a landmark trade deal with the European Union which had been at the heart of the crisis. Mr Yanukovych's last-minute rejection of the deal and decision to seek a Russian bailout triggered protests which led to his ouster.
Mr Poroshenko promised a dialogue with residents of eastern Ukraine and to guarantee their rights, including the right to speak Russian.
A ceasefire reached with pro-Russian armed rebels in the eastern provinces of Donetsk and Luhansk in September 2014 raised hopes that a political settlement that preserved Ukraine's territorial integrity might eventually be achieved, but the peace deal was seriously undermined when the rebels held controversial polls in November and elected leaders of the two "people's republics".
This move confirmed fears that the tensions between Kiev and eastern Ukraine could harden into a post-Soviet "frozen conflict", with rebel regions permanently under the protection of Russian troops.