Sunday's vote comes with tensions running high after a bloody upsurge in fighting in the east, where pro-Moscow separatists launched an insurgency against Kiev's rule seven weeks ago. (Agencies)
Prime Minister Arseniy Yatsenyuk issued an appeal for people to turn out to ‘defend Ukraine’, which has been in deep crisis since street protests forced out the Kremlin-backed regime in February.
"This will be the expression of the will of Ukrainians from the west, east, north and south," he said.
But the rebels warned they would prevent voting in their strongholds in the industrial heartland on the Russian border.
"If necessary we will revert to the use of force," said Denis Pushilin, a leader of the self-declared Donetsk People's Republic.
State election officials also admitted that they will only be able to open two of the 12 commissions responsible for tabulating ballots in the neighbouring separatist province of Lugansk.
However, in what could be a significant move in Ukraine's bitter confrontation with its former masters in Moscow, Russian President Vladimir Putin said on Friday that he would respect the outcome of the vote.
He also said that claims he was seeking to rebuild the Soviet empire were ‘absolutely untrue’.
Putin also held joint telephone talks with German Chancellor Angela Merkel and French President Francois Hollande, with the three leaders ‘‘expressing an interest in seeing that the presidential election in Ukraine was held in a peaceful and calm atmosphere,’’ the Kremlin said.
Suspicions about Putin's motives have soared since Moscow annexed the Black Sea peninsula of Crimea in March, inspiring Russian-speaking rebels to take up arms in the eastern rustbelt the following month.
"We will treat their choice with respect," Putin said on Friday, while blaming the West for sending the former Soviet state into a ‘full-scale civil war’.
"We are today working with those people who control the government and after the election we will of course work with the newly elected authorities."
He also dismissed suggestions that the worst standoff between Russia and the West since the collapse of the Soviet Union could be described as a ‘new Cold War’.
Sunday's vote comes with tensions running high after a bloody upsurge in fighting in the east, where pro-Moscow separatists launched an insurgency against Kiev's rule seven weeks ago.