KIEV, May 11 - Pro-Moscow rebels declared a resounding victory in a referendum on self-rule for eastern Ukraine, with some saying that meant independence and others eventual union with Russia as fighting flared in a conflict increasingly out of control, Reuters reported.

Organizers in the main region holding the makeshift vote on Sunday said nearly 90 percent had voted in favor.

Well before polls closed, one separatist leader said the region would form its own state bodies and military after the referendum, formalizing a split that began with the armed takeover of state buildings in a dozen eastern towns last month.

Another said the vote simply showed that the East wanted to decide its own fate, whether in Ukraine, on its own, or as part of Russia.

"Eighty-nine percent, that's it," the head of the separatist electoral commission in Donetsk, Roman Lyagin, said by telephone when asked for the result of a vote that the pro-Western Ukrainian government in Kiev has condemned as illegal.

Sunday's vote went ahead despite a call by Russian President Vladimir Putin on Wednesday to postpone it - a move that briefly raised hopes for an easing of tension. Western leaders have accused Putin of destabilizing Ukraine, a charge Moscow denies.

The European Union declared the referendum illegal and prepared to increase pressure on Russia on Monday by taking a first step towards extending sanctions to companies, as well as people, linked to Moscow's annexation of Ukraine's Crimea region.

A festive atmosphere at makeshift polling stations in some areas belied the potentially grave implications of the event. In others, clashes broke out between separatists and troops over ballot papers and control of a television tower.

Zhenya Denyesh, a 20-year-old student voting early at a university building in the rebel stronghold of Slavyansk, said: "We all want to live in our own country". But asked what he thought would follow, he replied: "It will still be war."

In the southeastern port of Mariupol, scene of fierce fighting last week, there were only eight polling centers for a population of half a million. Queues grew to hundreds of meters (yards) in bright sunshine, with spirits high as one center overflowed and ballot boxes were brought onto the street.

On the eastern outskirts, a little over an hour after polls opened, soldiers from Kiev seized what they said were falsified ballot papers, marked with Yes votes, and detained two men.

They refused to hand the men over to policemen who came to take them away, saying they did not trust them. Instead, they waited for state security officers to interview and arrest them.

On the edge of Slavyansk, fighting broke out around a television tower shortly before people began making their way through barricades of felled trees, tires and machinery for a vote the West says is being orchestrated by Moscow. The Ukrainian Defense Ministry said one serviceman was wounded. (rt/ez)