A new political party backed by the Kremlin and Prime Minister Vladimir Putin scored an unexpected success in elections for the lower house of parliament, as centrist and reformist parties made gains that could enable them to displace the Communists as the chamber's dominant political force, early returns showed today.

The outcome of Sunday's election for the State Duma appeared to be yet another major boost for Putin, who has earned wide public support in the last four months as he has vigorously prosecuted a military offensive against Chechen separatists in southern Russia.

The vote could help solidify Putin's standing as the heir apparent to Boris Yeltsin in next summer's presidential election and lead to a new, more cooperative relationship between the Kremlin and parliament after years of stalemate between Yeltsin and the Communists.

The early results take into account only the half of the 450-member chamber that is elected according to lists provided by political parties. Results for the other half, elected in individual districts, will become known in coming days; candidates in these races often run as independents, then choose their factions as the new parliament is formed.

With 67.33 percent of the ballots counted early today, the Unity party, the new group endorsed by Putin, had 24.94 percent of the vote. The Communists, who had formed the largest faction in the last parliament, were slightly ahead with 24.98 percent.

Among parties likely to enter the next Duma, the Fatherland-All Russia party, headed by Moscow Mayor Yuri Luzhkov and former prime minister Yevgeny Primakov, was in third place with 9.97 percent. The Union of Right Forces, a free-market party headed by another former prime minister, Sergei Kiriyenko, was next with 8.71 percent. Ultranationalist legislator Vladimir Zhirinovsky's bloc had won 6.42 percent of the vote, while the centrist Yabloko party, headed by Grigory Yavlinsky, had 5.93 percent. A party must win a minimum of 5 percent of the vote to gain representation in the Duma.

Election officials said the turnout was 60 percent, slightly less than the 64 percent who voted four years ago, but far more than the 36 percent turnout in the last U.S. congressional election.

Created just a few months ago by a coterie of Kremlin aides, the Unity party was the center of national attention after early returns foreshadowed its strong showing. The party had so little in the way of staff, platforms and experience that it has been dubbed a "virtual party" by some critics. It seemed to be disorganized even in victory; none of its leaders appeared at its election headquarters to bask in its startling success.

The party slate is headed by Sergei Shoigu, the minister for emergency situations--natural disasters, for example--who previously had played no role in national elective politics. Its other top two candidates were Alexander Karelin, a champion wrestler, and Alexander Gurov, a law enforcement official under the last Soviet leader, Mikhail Gorbachev.

It was Putin's recent endorsement of Unity that sent its poll ratings soaring. Putin was the "basic reason" the party did so well, said reformer Anatoly Chubais, who worked as top strategist for the Union of Right Forces. Without Putin, he added, "such results would have been hardly possible."

Putin, a KGB veteran who was appointed by Yeltsin on Aug. 9, now enjoys the highest public opinion ratings of a presidential hopeful since Yeltsin in 1991.

Putin had also lent his support to the Kiriyenko party, and his influence proved powerful today, even though he was not on the ballot.

"No one is afraid of the Communists any more and no one wants to be in opposition to Putin," said Michael McFaul of the Moscow Center of the Carnegie Endowment for International Peace. He said the election outcome would give Putin "a perfect platform on which to launch a campaign" for the presidency.

"Unity is indeed the party of power," acknowledged Kiriyenko, whose own brief tenure as prime minister in 1998 was characterized by conflict with parliament. "It gives the government possibilities to act constructively. Previously, if the government wanted to do something, it had to do it in a roundabout way. It could not get anything done directly."

Kiriyenko predicted that his party of young reformers would be able to join with Unity and Yabloko and others to form a centrist majority in the Duma--"a majority that will be ready to cooperate with the government and pass the necessary laws." But analysts said that any comprehensive calculations about the makeup of the next parliament will have to await the outcome of the elections in individual districts, the results of which were uncertain early today.

In the last Duma, the Communists were the largest bloc, and when their 158 seats were combined with allied groups they could often control the outcome of legislation. A bill needs 225 votes to pass on first reading; 300 votes are needed to override a presidential veto.

However, a rearrangement of parliamentary forces seemed certain after Sunday's vote. The party backed by the Kremlin in the last election--Our Home is Russia, headed by then-prime minister Viktor Chernomyrdin--came in third in the 1995 vote but failed to win enough votes this time to qualify for seats in the chamber.

Preliminary returns also suggested that Yavlinsky's Yabloko--the most pro-Western party in parliament, which had often cast itself in opposition to Yeltsin--had lost some public support. The party won 6.8 percent of the voting for slates in 1995 but also did well in individual races and held 45 seats in the last parliament. Several weeks ago, however, Yavlinsky expressed doubts about the offensive in Chechnya, and this apparently cost him at the ballot box, especially among hawkish younger voters.

The results also were a disappointment for Luzhkov and Primakov, whose aspirations seemed to be riding high last summer. There was speculation then that either or both of them might run for president and that their party could dominate parliament. But they ran a poor campaign and also were subjected to a no-holds-barred smear campaign by Kremlin aides and business tycoon Boris Berezovsky, a power broker close to Yeltsin's inner circle.

Nonetheless, their Fatherland-All Russia party appears to have won a toehold in the Duma. Luzhkov also was reelected Moscow mayor by a large margin, suggesting that he has preserved his local political base.

Gennady Seleznov, a Communist who was speaker of the Duma in the last session, was elected governor of the Moscow region. In Russia's Far East, Yevgeny Nazdratenko, a controversial and authoritarian figure, was reelected governor of the huge Primorsky region.

Also unexpected today was the reappearance of the "young reformers" in parliament in the party headed by Kiriyenko. They had failed to win party seats in the last election because of public disenchantment with market reform measures they had pushed, and at the outset of this year many thought they had little chance of crossing the 5 percent barrier. Today, Kiriyenko said, "We proved that liberal ideology is alive."

Rallying under the banner of "the Right Cause," the reformers targeted young voters using Western techniques. Chubais, the architect of Russia's mass privatization program, and now chief executive of the state electricity utility, said, "At the very beginning we were told, 'You guys will all get yourself buried in the same mass grave, and your cause is not the right cause but a dead cause.' But we kept working . . ."

Chubais also seized on support for the war in Chechnya as a campaign issue, declaring his strong support for Putin and the military offensive.

CAPTION: Moscow resident Dmitri Novikov, 74, uses a magnifying glass to examine the fine print on his ballot before voting yesterday in an election that could alter the makeup of parliament in favor of reformist forces.