An American billionaire who is spending $20 million of his own money this year to build a "new system" in the Soviet Union warns that civil war is likely if Western governments don't help more.

Hungarian-born George Soros, who is also spending another $20 million to aid Eastern Europe, described the process under way in the Soviet Union as "a circular descent, a disintegration. It's accelerating."In Eastern Europe, after the climax, the collapse of the system, you then had the beginning of a new system," said Soros, 61, in an interview. "In the Soviet Union, you don't have the beginnings of a new system. One climax is likely to be followed by next climax, until you go down the drain, until civilization comes to an end," he said.

To help prevent such a catastrophe, Soros has established 13 philanthropic organizations in Eastern Europe, the Baltic States, the Ukraine and Russia.

Through these foundations, his $40 million will be channeled to promising individuals involved in education, economics, law, the mass media or management, in the form of grants or travel in the West.

Also, Soros has called on Western governments to establish a fund of at least $3 billion to help Soviet republics stabilize currencies as they become convertible on the world market, and allow them to trade among each other as they move toward a market system.

Interviewed Thursday at the foundation he established in Moscow, Soros said war could flare if, for example, Russia tried to charge the Ukraine world market prices for oil, instead of subsidized prices under the Soviet system.

In response, he said, the Ukrainians might "impose a very heavy toll charge on the oil and gas passing through the pipelines" leading from Russia via Ukraine to the West, prompting the Russians to send troops and fighting to erupt.

The notion of war between Russia and the Ukraine is particularly frightening because large numbers of Soviet nuclear weapons are based in both republics, the two most populous in the Soviet Union.

Smaller civil wars already are under way between Armenia and Azerbaijan and in Georgia. And one nearly started this month in Chechen-Ingushetia, a Muslim enclave in southern Russia.

Most of the reformist economic advisers to Russian Federation President Boris N. Yeltsin and Soviet President Mikhail S. Gorbachev have received Soros' grants at some point in the past two years.