Ukraine profile - Leaders
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 Russian-backed separatist rebellion in the east of the country.
A billionaire chocolate factory owner, Mr Poroshenko 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.
The demonstrations were prompted by Mr Yanukovych's last-minute decision to reject a free deal with the EU - later signed by Mr Poroshenko - and seek a Russian bailout.
Only shortly before Mr Poroshenko was elected, Russia had responded to Mr Yanukovych's ouster by occupying the Crimea peninsula and running a referendum there in March 2014 in which an overwhelming majority voted to join Russia.
Conflict in east
Soon after, rebels in eastern Ukraine claiming to be acting on behalf of Russian speakers there declared two separatist "people's republics" centred on the cities of Donetsk and Luhansk, in the Donbass industrial area.
Mr Poroshenko launched an "anti-terrorism operation" against the rebels but it was repelled with covert military support from Russia in often bloody fighting.
A Russian-Ukrainian agreement to settle the conflict was mediated by France and Germany in the Belarusian capital Minsk in February 2015, but mainly succeeding in effectively creating a "frozen conflict".
Both Moscow and Kiev accuse each other of blocking the agreement, which requires Ukraine to grant the "people's republics" a special constitutional status, while demanding that the republics reintegrate into Ukraine and allow free and fair elections.
The EU's European Commission in 2016 praised Mr Poroshenko's government for carrying out "unprecedented" reform to strengthen democratic institutions and curb corruption.
But critics accuse the president of failing to make enough progress on combating graft and reining in Ukraine's powerful oligarchs.
The conflict in the east and the disruption of much of the country's business with Russia exacted a heavy toll on Ukraine's economy, which shrank by 6.% in 2014 and 10% in 2015, badly hitting living standards.
Fragile growth returned in 2016, but the recovery is painfully slow.
Progress on a core objective of Mr Poroshenko's government - ratification of an association agreement with the EU - was dealt a blow by a Dutch referendum vote against it in April 2016, albeit on a low turnout.