DONETSK, Ukraine (AFP) - Pro-Russian rebels claimed a massive turnout in a vote they held on Sunday to split east Ukraine into two independent republics, though Kiev slammed it as a "farce" amid Western fears it could lead to civil war.

Thousands of people queued in front of a limited number of polling stations in the restive provinces of Donetsk and Lugansk to cast their ballots, AFP journalists in several towns reported.

"I want to be independent from everyone," said ex-factory worker Nikolai Cherepin as he voted yes in the town of Mariupol, in Donetsk province. "Yugoslavia broke up and they live well now".

Insurgent leaders asserted that more than 70 per cent of the electorate in the two regions - home to seven million of Ukraine's total population of 46 million - had slid voting slips into transparent ballot boxes.

There was no way to verify that assertion however. No independent observers were monitoring the vote, which took place in the absence of any international support - even from Moscow, which had urged it be postponed.

No violent incidents were reported during polling, but tensions remained high amid an ongoing military operation ordered by Kiev against the rebels.

Early Sunday, an isolated clash occurred on the outskirts of the flashpoint town of Slavyansk as militants tried to recapture a TV tower, but polling in the centre was unaffected.

Roman Lyaguin, the head of Donetsk's self-styled electoral commission, told reporters that voter turnout across the province was 70 per cent four hours before polls were to close at 8pm (1700 GMT). Lugansk's rebels put their province's turnout at more than 75 per cent.

Lyaguin added that results would not be in until Monday, but already appeared confident that the outcome would be in favour of independence. After the results, he said, "there will likely be a period of negotiation with the authorities in Kiev".

The hastily organised poll fell short of Western balloting norms. Notably, curtained booths were not set up in every town taking part, and polling staff lacking electoral rolls registered anyone who turned up to vote.

Kiev called the process a "criminal farce" that had no legal or constitutional validity.

It said the vote was "inspired, organised and financed by the Kremlin".

Western nations backing the Ukrainian government also dismissed the regional "referendums".

They were "null and void," French President Francois Hollande said on a visit to Azerbaijan.

Britain's Foreign Office issued a statement calling the "illegitimate, so-called referendum" regrettable.

It added that a nationwide presidential election Ukraine is scheduled in two weeks that will give "all Ukrainians... a democratic choice".

Britain also added its weight to a French and German warning of "consequences" against Russia if that election were to be scuppered.

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.

If Ukraine's May 25 presidential election is stymied, the West has warned of immediate sanctions to cripple broad sectors of Russia's economy.

But questions over the vote's validity or the geopolitical consequences appeared far from the minds of those lining up to vote in Ukraine's east on 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 she used was the one separatists and Russian state media use to describe Ukraine's Western-backed government.

Mariupol, a city of 500,000 inhabitants, saw some of the longest voting lines because only four polling stations were operating.

Anti-Kiev sentiment was riding high there 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 their anger against the government.

"I know many people who were strongly anti-Russian but after what happened in Ukraine with the slaughter of people, with what happened in Odessa, a lot of them changed their position to pro-Russian," said Yaroslav, a post-graduate student who gave only his first name as he queued to vote in Donetsk.

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

"It's an illegitimate action carried out by an unknown group of people who took over the administration buildings and run around with weapons in their hands," growled one Donetsk resident, Anatoli Kozlovskiy.

Another, Alice Skubko, added: "I understand why they are going to vote, because there was propaganda, illegal propaganda. People don't understand what they are doing, they don't understand the consequences of their action if they vote in this referendum." One 20-year-old fireman in Mariupol, Ivan Shelest, told AFP: "If this goes through and they really become the Donetsk Republic it will be a disaster. What sort of people will lead it? It will be chaos - even worse than now." The chief of staff for Ukraine's interim presidency, Sergiy Pashinskiy, told reporters in the Kiev: "This isn't a referendum, this is a pitiful attempt of the terrorists and murderers to use people of the Donetsk and Lugansk regions to cover up their crimes." The US State Department said the referendums were illegal and "an attempt to create further division and disorder".

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