World Bulletin/News Desk

Scores of armed pro-Russian separatists gathered for several hours outside the gated home of Ukraine's richest man, Rinat Akhmetov, in the eastern city of Donetsk on Sunday as Ukrainians voted for a new president.

Coal and steel billionaire Akhmetov, whose factories and mines employ about 300,000 people, denounced the rebels last week, accusing them of "genocide", and urged people to vote on Sunday despite intimidation and threats from the separatists.

The rebels have prevented voting in parts of Russian-speaking eastern Ukraine where they have declared "people's republics" outside Kiev's control. No polling stations opened in Donetsk, a city of a million people.

The 47-year-old Akhmetov, who also owns Ukraine's most successful soccer club Shakhtar Donetsk, was in the capital Kiev when about 200-300 separatists and supporters advanced on his residence, a spokesman said.

"Mr. Akhmetov is today in Kiev. He had intended to return to Donetsk to vote but as you can see from what is happening there and on the streets this has not been possible," said Jock Mendoza-Wilson at Akhmetov's company, System Capital Management.

Some of the men were masked and were aggressive towards journalists as they gathered by the high walls of Akhmetov's suburban residence, which is protected by armed security guards.

But after several hours tempers calmed and most people left.

A leader of one group of about 30 heavily armed fighters, Alexander Timofeyev, said they had come only to keep order after a crowd of demonstrators had gathered to confront Akhmetov.

Alexander Boroday, one of the leaders of the self-proclaimed "Donetsk People's Republic" said negotiations had begun with Akhmetov and a picket would be maintained outside his residence until there had been a "positive result".

He did not say what demands they were making on the multi-billionaire but earlier separatist representatives said they were insisting he make tax payments into the Donetsk People's Republic's budget, Interfax news agency said.