Mikhail S. Gorbachev warned of civil war if radicals promoting recent street demonstrations succeed in ousting him as president.

In distancing himself from the forces of radical reform in favor of Communist Party traditionalists, Gorbachev set the tone before a March 17 national referendum on holding the Soviet Union together. The radical reformers have said they will try to use the vote as a referendum on Gorbachev's six years in power.In his speech Tuesday night, Gorbachev singled out his main political rival, Russian Federation President Boris N. Yeltsin.

The Russian leader last week accused the Soviet president of abandoning perestroika, his program of social and political reform, for personal power. Yeltsin demanded Gorbachev's resignation.

"The democrats are striving for power," Gorbachev said in his speech, referring to Yeltsin and other reformers. The Soviet leader was speaking to intellectuals in the Byelorussian republic capital of Minsk on his first domestic trip outside Moscow in six months.

"Since their initial plan for a lightning capture of power by legal means through the Congress and Supreme Soviet (legislative bodies) did not work, they decided to use what some analysts define today as neo-Bolshevist tactics," Gorbachev said.

"You know what I mean. It's the transition of the struggle to the streets: organizing demonstrations, rallies, strikes and hunger strikes."

The anti-Communist opposition has staged three huge rallies in Moscow since the Kremlin's Jan. 13 military crackdown in the Baltics, with increasing calls for Gorbachev's resignation.

"In the absence of positive programs, they address the people - the working class - over the heads of the parliament, with an appeal to dissolve this and that, and force the president to resign," Gorbachev said. "And they might succeed."

He warned: "We categorically reject any attempts to repeat the forcible capture of power which would almost inevitably be followed by a civil war."

It was Gorbachev's first public comment on Yeltsin's nationally televised demands, which have been condemned by the central press and by national and Russian lawmakers. The Russian legislature plans a no-confidence vote on Yeltsin's 10-month-old presidency.

Soviet newspapers, usually slow to report on news events, carried long reports Wednesday of Gorbachev's speech and tour of a Minsk tractor factory. His attack on Yeltsin was included in the coverage.

Gorbachev said he has been hampered in the past 18 months "by the most intense power struggle." He said reformers such as Yeltsin and Moscow Mayor Gavriil Popov want to dismember the Soviet Union.