Strong Showing by Yeltsin Fails to End Power Struggle : Russia: President refrains from claiming victory in referendum. But supporters urge him to act decisively, while foes warn him against trying to curb Congress.

Heartened by a strong vote of confidence in President Boris N. Yeltsin, his supporters Monday urged him to use the mandate to hasten democratic reforms. But his opponents warned that the battle for power in Russia is far from over.

Yeltsin, who had hoped the referendum would end a paralyzing power struggle between himself and the conservative Parliament, refrained from claiming immediate victory in the referendum and instead awaited final official results that are expected today.

But his political foes warned him not to try to use his victory to take power away from Parliament--the Congress of People’s Deputies, a Communist-dominated body whose members were elected before party rule ended with the collapse of the old Soviet Union.

“If he tries to exploit his success through some unconstitutional measures, I suppose that will bring this badly split society to a brink of confrontation and civil war,” said Vladimir B. Isakov, a Congress member and leader of the National Salvation Front, a coalition of Communist and nationalist political groups.

The latest unofficial returns from Sunday’s national referendum showed that 59% of the voters expressed confidence in Yeltsin and 54% supported his pro-market economic policies, according to the Interfax news service.

Democratic politicians said the referendum gives Yeltsin the strongest mandate he has had since he led the political and military elements that defeated a hard-line putsch in August, 1991.

“We urge the president to fully use the results of the victory and not to indulge in inexplicable inaction, as was the case in the post-August, 1991, days,” Sergei N. Yushenkov, a democratic member of Parliament, told a news conference.

Yeltsin has been criticized for failing to use his post-coup momentum to abolish Soviet-era institutions, including the Congress of People’s Deputies, that have worked ever since to defeat democratic and pro-market reforms.

In Washington, a senior government specialist in Russian affairs told The Times on Monday that Yeltsin’s victory was “on the high side” of official U.S. expectations.

“What I now expect is that Yeltsin’s opponents will be in more of a defensive mode,” this analyst said. “It’s going to be harder for them to attack Yeltsin. But if Yeltsin sits back, he’ll be back to where he was before.”

American officials believe political battles between Yeltsin and his opponents will intensify in the coming months. The senior U.S. official said Yeltsin could seize the initiative by proposing new economic reform measures and by calling for new parliamentary elections in the late summer or fall.

President Clinton telephoned Yeltsin on Monday to congratulate him. After a 15-minute conversation, he told reporters that the referendum had been an “outstanding victory” for the Russian president.

“This is a very, very good day not only for the people of Russia but for all the people of the world,” Clinton said. “ . . . I think the reaffirmation of his policies really is a tribute to the farsightedness of the Russian people.”

Yeltsin spent the day Monday analyzing the preliminary results and consulting his advisers on a “plan of action” that will be launched only after final referendum results are announced, said presidential spokesman Vyacheslav V. Kostikov.

Before the referendum, Yeltsin told reporters that if the public voted in his favor, he would sell off state-owned land to gardeners, crack down on economic crimes and work toward adoption of a new, Western-style constitution.

His opposition made it clear Monday that they did not consider the referendum an all-out victory for the president.

Isakov said the results only make it look as if the president has the confidence of most of the people. In reality, he asserted, more than a third of all voters were too discouraged even to make it to the polls. Although Yeltsin got 59% of the vote, that represented only 38% of all eligible voters because the turnout was 65%, according to Interfax.

The Public Committee for the Defense of the Constitution and Constitutional System, a coalition of anti-Yeltsin political groups, published a statement remarking on the “healthy new situation brought about by the political and moral defeat of the Russian president.” The voter turnout, low by Soviet standards, was “catastrophic for the president,” the statement said.

Parliamentary Chairman Ruslan I. Khasbulatov, Yeltsin’s most powerful enemy, was far from contrite, despite the fact that preliminary returns showed that more than two-thirds of those who went to the polls voted for early new elections for Parliament. That vote fell short of the majority of all 105.5 million eligible voters, which the Constitutional Court ruled was necessary to mandate early elections.

“There were no clear winners or losers,” Khasbulatov said during a meeting of leaders of the Supreme Soviet, the country’s standing legislature, whose members are all drawn from the larger Congress of People’s Deputies.

Pro-Yeltsin lawmakers said that members of the Parliament are fooling themselves if they think the referendum’s results represent anything but a clear denunciation of their work.

“If a high percentage of voters say to their deputies: ‘Gentlemen, you are not coping. Gentlemen, we are tired of you,’ then any politician who has any sense of morality, any statesman with a sense of responsibility must decide either to hold an early election or listen to the voice of the people and support the president,” said Boris A. Zolotukhin, a pro-reform member of the Supreme Soviet.

But Khasbulatov showed no sign of any retreat. In the meeting with other legislative leaders, he threatened to crack down on the media, accusing them of misleading the electorate. Society, he said, “can no longer stand the information terror.”

Yeltsin’s government struck back, warning against any move to limit the freedom of the mass media.

“Suffering a clear defeat at the referendum, sympathizers of barracks-type communism began to look for culprits,” Mikhail N. Poltoranin, a close Yeltsin adviser and head of the Russian Federal Information Center, said in a statement. “We’d like to tell the majority of deputies: Your bad luck lies not in the press and alleged (vote) forgeries you are looking for with a magnifying glass. Your bad luck lies in yourselves.”

Vladimir O. Boxer, a democratic politician and a leader of the pro-Yeltsin referendum campaign, said the degree of backing for Yeltsin’s economic policies resulted from a strong advertising blitz that began just days before the referendum. It told voters that supporting the president meant voting “yes, yes, no, yes”--or yes to Yeltsin, yes to his reforms, no to early presidential elections and yes to early parliamentary elections.

According to unofficial results reported by Interfax, which include returns from 79 of the 88 voting regions in Russia, 68% of those who went to the polls voted for early elections for Congress, but they represented only 43% of all registered voters. And 49% of those who voted, or 31% of the electorate, supported early election for the presidency.

While Yeltsin won a clear majority, the results showed that his popularity varies greatly from one part of the vast Russian nation to another.

In the gold-rich region of Magadan in the Russian Far East, 74% of voters said they trusted the Russian president. Yeltsin also received overwhelming support in Moscow, St. Petersburg and Ekaterinburg--the president’s hometown.

But in the Penza region, a heavily agricultural area several hundred miles southeast of Moscow, 52.6% of voters gave Yeltsin a vote of no confidence.

Reporter Sergei Loiko of The Times Moscow Bureau and Times staff writer Jim Mann, in Washington, contributed to this report.

Yeltsin’s Vote, by Age, Education

A breakdown of those who gave their approval to Question No. 1 in Sunday’s referendum:

“Do you have confidence in Russian President Boris N. Yeltsin?” Sex (YES) Men: 62.2% Women: 64.2% Age 18-25: 68.4% 25-40: 66.4% 40-55: 62.0% 55-90: 58.7% Level of education Higher education: 66.7% Secondary education: 62.6% Below secondary education: 60.0% Profession Business: 83.8% Manager: 64.7% Expert, clerk with higher education: 65.7% Army officer, soldier, police: 64.6% Clerk with secondary education: 71.8% Blue-collar, highly qualified: 62.2% Blue-collar, low qualified: 60.9% Student: 63.9% Pension: 56.6% Housewife: 65.6% Unemployed: 62.7% Source: An exit poll of voters on the Russian referendum, conducted Sunday by the Russian Center for Public Opinion and Market Research. Based on interviews with about 5,000 adults after they cast their ballots. Margin of error is plus or minus 3.5%.