KIEV, Ukraine — A bitterly divided Ukraine voted Sunday in a presidential election seen as the most important in the country's history as it battles a deadly pro-Russian insurrection in the east.

Turnout was brisk in the capital Kiev and the west where long queues were reported but across the rebel-controlled industrial east, most polling stations remained closed.

"Ukraine is now another country so I don't see why we should take part in this election," said one woman in the rebel-held city of Donetsk who gave her name as Elisabeta.

"It doesn't matter what the result is, it doesn't concern us today."

The West regards the vote as crucial to prevent Ukraine from disintegrating further after Russia seized the Black Sea peninsula of Crimea in March in retaliation for the ouster of pro-Kremlin president Viktor Yanukovych.

The packed field of candidates features clear frontrunner Petro Poroshenko — a billionaire chocolate baron and political veteran who sees Ukraine's future anchored to Europe and 17 far less popular hopefuls that include ex-premier Yulia Tymoshenko.

"The first thing we must do is bring peace to all the citizens of Ukraine. Armed people must leave the streets of towns and cities," Poroshenko said after casting his ballot in Kiev.

He called for "direct dialogue" with the people of Donetsk and Lugansk regions, where rebels declared independence earlier this month after referendums branded as shams by Kiev and the West.

But in those regions, the hub of Ukraine's coal and steel industries, only nine of the 34 electoral constituencies were open, according to the central election commission. 

Even before polling day, election officials had reported numerous cases of intimidation and attacks on polling centers and rebels threatened Saturday they would disrupt the vote "by force if necessary."

Violence flared on the eve of the vote in eastern flashpoint of Slavyansk, where one Italian photographer was killed and a French photographer and his Russian translator were wounded after being caught in a gunbattle.

It was the first reported death of a journalist in east Ukraine, where one member of the Ukrainian defense force was also killed in overnight fighting.

President Vladimir Putin, facing the threat of further Western sanctions, had appeared to make a major concession Friday by saying he was ready to work with the new Kiev team.

"We understand that the people of Ukraine want their country to emerge from this crisis. We will treat their choice with respect," he said.

Russia also said it has started withdrawing from Ukraine's border around 40,000 soldiers and dozens of tank battalions whose presence had raised deep suspicions about Russia's next move.

But in a fresh sign of Moscow's plans to continue exerting pressure, Prime Minister Dmitry Medvedev announced plans Sunday to visit Crimea, which has been formally incorporated as a part of Russia and where no voting was taking place.

Ukraine has mobilized more than 82,000 police and 17,500 volunteers to ensure security for the vote, being overseen by 1,200 international monitors.

The interior ministry said 29,000 of the country's 33,500 polling stations had opened on time, with early turnout particularly strong in Kiev, where 55-year-old housewife Nelia Issayenko said she was voting "so that Russia leaves us alone."

The election should give the new president a stamp of legitimacy as he or she battles against the insurgency and tries to repair relations with Ukraine's former masters in the Kremlin.

However, opinion polls show Poroshenko falling just short of the 50-percent threshold needed to avoid a second round on June 15, and three weeks of further political uncertainty.

The ballot was called by Kiev's interim leaders who took power after Yanukovych fled in the bloody climax of months of protests sparked by his rejection of a historic EU alliance.

The charred buildings and flower-heaped barricades still crisscrossing Kiev's Independence Square — also the cradle of the 2004 Orange Revolution that first shook Russia's historic hold on Ukraine — serve as poignant testimony to the more than 100 people killed in the bloody winter days.

At least 150 people have been killed in the east since the separatists took up arms against Kiev, while another 42 perished in fighting and a fire in the southern city of Odessa, according to an AFP tally based on UN and Ukrainian government figures.

Ukraine is hoping that up to $27 billion in global assistance it won after the old regime's fall may help avert threatened bankruptcy and revive growth in the recession hit country.

But the new leadership will also have to negotiate with Russia over vital supplies of gas, with Moscow threatening to halt shipments if Ukraine does not pay a bill by early June.

Voting closes Sunday afternoon with the first results expected Sunday night.

"I hope this election will launch a process of change for the better . . . but I don't expect a magic wand," said Inna, a voter in the eastern city of Kharkiv that remains in Kiev's control.