Russia will recognize the outcome of Ukraine's presidential vote this weekend, President Vladimir Putin promised Friday, voicing hope that Ukraine's new leader would halt the military operation against separatists in the east.

But clashes between pro-Russia separatists and government forces appeared to be heating up, leaving 20 more rebels and one soldier dead, Ukraine's Defence Ministry reported Friday.

Up to 500 insurgents attacked a convoy of government troops in one clash Thursday outside the eastern village of Rubizhne that left 20 insurgents dead, the ministry said. It also said one soldier was killed early Friday in a separate clash near the same area.

In Kyiv, Ukraine's caretaker president urged all voters to take part in Sunday's crucial ballot to "cement the foundation of our nation." Yet pro-Russia insurgents were still battling government forces Friday in eastern Ukraine, where a vote boycott and threats against election workers were disrupting the prospects of the ballot taking place.

AP journalists in the east saw three dead from Friday's fighting a day after insurgents killed 16 Ukrainian soldiers at a checkpoint. One rebel leader said 16 more people died in fighting Friday — 10 soldiers, four rebels and two civilians —but there was no immediate way to verify his statement.

Speaking at an investment forum in St. Petersburg, Putin said Russia will "respect the choice of the Ukrainian people" and will work with the new leadership. He said Russia wants peace and order to be restored in its neighbour.

Ruble surges

Markets rallied and the ruble surged in value against the dollar Friday as the CEOs and economic experts at the forum praised Putin's efforts to defuse the tensions.

An Ukrainian soldier secures an area near the site where pro-Russian rebels killed thirteen Ukrainian servicemen in eastern Ukraine on Thursday. Fighting continues in Ukraine's east between pro-Russia insurgents and government forces days before a presidential election. (Yannis Behrakis/Reuters) The Russian leader also voiced hopes of mending ties with the United States and the 28-nation European Union, which have slapped asset freezes and travel bans on members of Putin's entourage and had threatened to introduce more crippling sanctions if Russia tried to derail Sunday's vote in Ukraine.

Alexei Makarkin, deputy head of the Moscow-based Center for Political Technologies think-tank, said Putin's comments reflected a desire to avoid another round of Western sanctions. He added, however, that Russia's relations with Ukraine will be unlikely to normalize any time soon.

Twenty-one candidates are competing Sunday to become Ukraine's next leader. Polls show billionaire candy-maker Petro Poroshenko with a commanding lead but falling short of the absolute majority needed to win in the first round. His nearest challenger is Yulia Tymoshenko, the divisive former prime minister, who is trailing by a significant margin. If no one wins in the first round, a runoff will be held June 15 — and most polls predict Poroshenko's victory in that contest.

Poroshenko, the likely winner, will probably focus on forging close ties with the West, said Makarkin, the analyst.

"He may take Russia's interests into account, but only to a limited extent," he said. "A quick warming of ties is unlikely."

Putin blames Western 'snobbery'

Russia annexed the Crimean Peninsula in March, grabbing a large section of Ukraine's Black Sea coastline and triggering the worst crisis in relations with the West since the Cold War.

Putin blamed the crisis on what he described as Western "snobbery" and a stubborn reluctance to listen to Russia's economic and security concerns. He said the sanctions on his inner circle were unfair.

He insisted Russia had nothing to do with what he described as the "chaos and a full-scale civil war" in Ukraine, saying that was triggered by the West's support of a "coup" which chased Ukraine's pro-Russian president from power in February.

"They supported the coup and plunged the country into chaos, and now they try to blame us for that and have us clean up their mess," he said.

Putin also alleged that by pressing the EU to impose stronger sanctions against Russia, the U.S. was trying to weaken a competitor.

"Maybe the Americans, who are quite shrewd, want to win a competitive edge over Europe by insisting on introducing sanctions against Russia?" he asked.

On a more positive note, he hoped that "common sense will push our partners in the United States and Europe toward continuing cooperation with Russia."

In a live televised address from Kyiv, Ukraine's acting President Oleksandr Turchynov, who is not running in Sunday's election, emphasized the importance of the vote to choose a new leader.

"Today, we are building a new European country, the foundation of which was laid by millions of Ukrainians who proved that they are capable of defending their own choice and their country," Turchynov said. "We will never allow anyone to rob us of our freedom and independence, turn our Ukraine into a part of the post-Soviet empire."

Authorities in Kyiv had hoped that a new president would unify the divided nation, where the west looks toward Europe and the east has strong traditional ties to Russia. But they have now acknowledged it will be impossible to hold the vote in some areas in the east — especially in Donetsk and Luhansk, where insurgents have declared independence and pledged to derail the vote. Election workers and activists say gunmen there have threatened them and seized their voting roles and stamps.

Joao Soares of the Organization for Security and Cooperation in Europe said Friday he expects problems with voting in "less than 20 percent of the polling stations."

Fighting, meanwhile, still cast a shadow over the presidential vote.

Associated Press journalists saw the bodies of two Ukrainian soldiers Friday in the village of Karlivka, 20 kilometres from the eastern city of Donetsk. One body was lying along the road, the other behind a burnt-down cafe near a bridge controlled by pro-Russia insurgents.

A spokesman for the pro-Russia rebels, who identified himself only by his first name, Dmitry, for security reasons, said 10 government soldiers, four of his men and two civilians were killed in fighting Friday. He spoke in Karlivka.

At another site outside Donetsk, AP journalists saw another body lying near a checkpoint manned by insurgents.

Fighting also continued around the eastern city of Slovyansk, where Ukrainian government forces retaliated against rebel fire, damaging several houses. There was no word on casualties.