KIEV, Ukraine — They are not sleeping in tents in Independence Square, but Ukraine’s ultra-wealthy businessmen, known as the oligarchs, perhaps pose as grave a threat to President Viktor F. Yanukovich as the demonstrators on the streets of this capital city.

“Do you think there is a big difference between people on the street and people with big business?” said the most visible, and the most pro-Western, of the oligarchs, Petro Poroshenko, a shipping, confectionery and agriculture magnate whose television station has been broadcasting round the clock from Independence Square.

“There is no difference in their love of their own country,” he said in an interview in the lobby of the Ukraine Hotel, overlooking the square, where the protesters appeared as miniature silent figures, waving flags and milling about bonfires. “At the end of the day, we are all talking about the modernization of the economy and the country.”

Protesters may be occupying government buildings and staging loud rallies calling for the government to step down, but behind the scenes an equally fierce — and perhaps more decisive — tug of war is being waged among a very small and very rich group of oligarchical clans here, some of whom see their future with Europe and others with Russia. That conflict was ignited, along with the street protests, by Mr. Yanukovich’s decision to halt free trade talks with the European Union last week.