Pro-Russian rebels claimed voters in eastern Ukraine massively backed independence in a disputed poll that Kiev and the West dismissed as an illegal "farce", with complete results awaited Monday.

A total of 89 percent of voters cast ballots in favour of self-rule in the Donetsk province, one of two regions holding "referendums" on Sunday, according to the insurgents' self-styled electoral commission.

Ten percent voted against, and turnout was 75 percent, the commission's chief, Roman Lyagin, told a news conference in the provincial hub of Donetsk.

"These can be considered the final results," he said, less than two hours after polls closed.

There was no immediate word of results from Lugansk, the other province holding a similar referendum. But the vote for independence there was expected to be similar to Donetsk's, or even exceed it.

The two regions are home to seven million people, out of Ukraine's total population of 46 million.

Kiev called the vote a "criminal farce" that had no legal validity, arguing that it was "inspired, organised and financed by the Kremlin".

The West also rejected the self-determination poll amid fears that these disputed votes could hasten the break-up of the former Soviet Republic and lead to a civil war on Europe's eastern edge.

The votes are "null and void," French President Francois Hollande said during a visit to Azerbaijan.

Swedish Foreign Minister Carl Bildt, writing on his official Twitter feed, said: "Figures from fake referendums in Eastern Ukraine likely to be fake. No way of knowing even turnout."

- 'Illegal' vote -

The European Union issued a statement calling the vote "illegal" and stating that the outcome would not be recognised. Its organisation "runs counter" to efforts "to de-escalate tensions," the office of EU foreign policy chief Catherine Ashton said.

Britain's Foreign Office stressed that a nationwide presidential election due to be held on May 25 in Ukraine would provide "all Ukrainians... a democratic choice".

European foreign ministers will meet from 0730 GMT Monday to outline possible new sanctions against Russia if the scheduled election is disrupted.

If Ukraine's presidential election is stymied, the West has warned of immediate sanctions to cripple broad sectors of Russia's economy.

"They, the Russians, may feel that somehow they're winning. But the world is not about just short term," US Defense Secretary Chuck Hagel told ABC television.

Also on Monday, for the first time in the months-long crisis, EU Council president Herman Van Rompuy, who represents the bloc's 28 leaders, will fly to Kiev to meet the interim government.

The EU so far has already imposed asset freezes and visa bans against 48 Russians and Ukrainians.

- 'The first people's government -

There was no way to independently verify the vote results. The rebels had prevented foreign media from observing ballot counting, and voting had taken place with no neutral monitors, incomplete electoral rolls, and a haphazard registration procedure that did nothing to prevent multiple voting.

But just before the announced figures, the rebel leader in Donetsk, Denis Pushilin, gave an interview to AFP boasting that the results would "create the first people's government".

"This is what we fought for, for the majority to decide the destiny of the region and we achieved that goal," he said.

The referendums took place under tension in east Ukraine, where troops are waging an ongoing offensive against pro-Moscow gunmen.

Isolated violence flared in some towns. A freelance photographer working for AFP saw a gunman in a group of pro-Kiev militants fire into a crowd of pro-Russian activists in the town of Krasnoarmiysk, badly wounding at least two.

A skirmish also occurred early in the day on the outskirts of the flashpoint town of Slavyansk, where rebels tried to grab back a TV tower.

The United States and the European Union see Russian President Vladimir Putin's hand in the unrest that has gripped eastern Ukraine since early April. They believe he is seeking a repeat of the scenario that led to Russia's annexation of Crimea in March.

Putin on Wednesday called for the rebels to put off the independence vote but did little to allay the West's suspicions.

- Independence 'will be hard' -

Questions over the vote's validity or the geopolitical consequences appeared far from the minds of those who lined up to cast ballots Sunday.

Tatiana, a 35-year-old florist voting in the regional hub of Donetsk, told AFP: "If we're independent, it will be hard at the beginning but it will be better than being with the fascists."

The "fascist" epithet was the one separatists and Russian state media use to describe Ukraine's Western-backed government.

Anti-Kiev sentiment was riding high after a fierce firefight between troops and rebels that killed up to 21 people on Friday.

Coupled with deadly clashes and an inferno in Odessa a week earlier that killed 42 people, many Russian-speaking Ukrainians who had been wavering decided to vote against the government.

Others, though, were strongly opposed to the rebels and the referendums.

A poll released Thursday by the Pew Research Centre in the United States suggested 70 percent of Ukrainians in the east want to stay in a united country, while only 18 percent back secession.