Support for the Communists and the Liberal Democratic Party is growing at the expense of United Russia and A Just Russia, but the State Duma elections in December shouldn't shatter the current four-party configuration dominated by United Russia, according to a survey released Wednesday.

Unlike regular surveys, the forecast by state-run VTsIOM pollster combines a population poll with prognoses by 13 political analysts and sociologists.

If the elections were held this month, United Russia would win 58.3 percent of the vote, down from almost 63 percent last November, VTsIOM said.

The Communist Party increased its support from about 12 percent to 14.7 percent over the period. The Liberal Democratic Party also boosted its ratings from 6.9 percent to 9.8 percent, while A Just Russia is teetering on the brink of the 7 percent threshold with 7.3 percent, down from 8.9 percent in November.

None of the country's other three registered parties would have won seats. The Patriots of Russia would get 1.9 percent, Yabloko 2.8 percent, and the revamped Right Cause 4.1 percent, admittedly up from 2.6 percent in November.

The poll, held in June, covered 1,600 people and had a margin of error of 3.4 percentage points. VTsIOM did not identify the 13 analysts questioned for the survey.

The pro-business Right Cause party is the wild card of the election season, with its new leader, billionaire Mikhail Prokhorov, promising to make it the second-biggest faction in the next Duma.

But the party "will not succeed by using liberal ideology," Sergei Mikheyev, head of the Center of Political Conjuncture of Russia, said at a news conference organized by VTsIOM to unveil the survey.

VTsIOM head Valery Fyodorov called Right Cause's electioneering a personal advertising campaign for Prokhorov, who made headlines in 2007 when he was detained and later cleared during a prostitution investigation at the French resort of Courchevel. Prokhorov also angered unions by proposing a 60-hour work week last year.

"Most Russians know Prokhorov from the scandal at Courchevel and the proposal to introduce the 60-hour work week," Mikheyev said.

Fyodorov said it was "a big question whether Prokhorov would change so much to attract more voters in the remaining time."

As for the other parties, A Just Russia suffered from the recent dismissal of its leader Sergei Mironov as the Federation Council speaker, Fyodorov said. In addition, the party has been "deprived of a key object for criticism" after St. Petersburg Governor Valentina Matviyenko agreed to trade her job for Mironov's speaker seat, he said.

The Liberal Democratic Party's rating is growing because of a rise in nationalistic moods that the party has tried to cater to recently, Fyodorov said.

The Communist Party has a permanent electoral base of about 18 percent, but part of its supporters mobilize only on the eve of elections, which spells more gains for the party as December draws near, Mikheyev said.

Moreover, some Communist voters who swung toward A Just Russia, created in 2006 as a pro-Kremlin alternative to the Communists, at the last Duma elections, will come back, Mikheyev said.

As for United Russia, Mikheyev blamed its slipping popularity on a "number of recent technological catastrophes." He did not elaborate, but recent incidents include plane crashes in Petrozavodsk last month and the Tomsk region in early July, which killed a total of 54, and the sinking of the cruise ship Bulgaria last week, killing a presumed 129.

Meanwhile, United Russia and its new electoral ally, the All-Russia People's Front, finished accepting nominations for joint primaries Wednesday. Campaigning was to start Thursday and proceed parallel to the primaries, which are to wrap up by Aug. 25, the party said on its web site.

United Russia is to reserve 150 of the 600 seats on its party list for members of the front, created by its leader, Prime Minister Vladimir Putin, to give broader representation in the Duma to nonpolitical groups.