Russian President Vladimir Putin's United Russia party will name its candidate for next year's presidential vote on December 17 when it could become clearer who Putin wants to be his successor.

The announcement will be made at the party's congress but it is not certain the United Russia nominee will be Putin's final choice. Analysts expect the Russian leader to keep his options open for as long as possible.

One of the first questions at the congress will be about the candidate in the presidential election and it will be considered on December 17, United Russia leader Boris Gryzlov told a news conference on Friday.

United Russia achieved a landslide victory in last weekend's parliamentary election.

Russia's constitution bars Putin from running for a third consecutive term and he has said he will step down after his replacement is elected. The 55-year-old has also said he is likely to endorse one of his team to replace him.

Putin's close aides, first deputy prime ministers Sergei Ivanov and Dmitry Medvedev, are regarded as the most obvious candidates as his preferred successor. Prime Minister Viktor Zubkov is also considered a possibility by analysts.

Support from Putin, Russia's most popular politician, is the key to victory for any candidate in the presidential election on March 2 when the weak and fractured opposition is unlikely to be a strong player.

Supporters of outspoken Kremlin critic Mikhail Kasyanov nominated him on Friday to run for president. Kasyanov, Putin's prime minister until he was sacked in February 2004, said he would apply formally on Monday to run in the election.

Kasyanov represents Russian liberals. Analysts say the majority of voters associate them with the economic and political chaos of the 1990s.

Underlining the uncertainty about how and when Putin will put forward his chosen successor, Gryzlov said United Russia was ready to back any scheme proposed by the Russian leader.

Several political forces, including a new movement called For Putin!, have been vying for the right to nominate the main Kremlin-endorsed candidate.

Asked whether United Russia could back a candidate proposed by the For Putin! movement, Gryzlov said: I said the party congress will consider a candidate. This suggests any option and we will specify our position closer to the congress.

OPTIONS

Putin led United Russia's list of candidates in the parliamentary election and has associated himself closely with the party. But he is not a member and has kept channels open to rival pro-Kremlin groups.

Gryzlov said he would welcome Putin becoming a party member. Vladimir Vladimirovich Putin has led United Russia's election list, he has associated himself with the party, he said.

It's up to him to decide whether he formally joins the party. I hope he becomes a party member.

The Kremlin has not said if Putin will attend the December 17 congress in a Moscow conference hall.

Gryzlov indicated his party, which has more than two thirds of seats in the lower house of parliament, was the best election platform for Putin's successor.

Our candidate will be elected by the majority of citizens of this country, Gryzlov said. I hope the candidate who will be considered at the December 17 congress can get popular support and win in the first round.

Some analysts had speculated Putin could become speaker of parliament when he leaves the presidency. There has also been speculation that Gryzlov, who was speaker in the outgoing parliament, could be tapped to be Putin's successor.

Gryzlov appeared to rule this out.

We have decided to discuss at the congress candidates for the future party leader and parliamentary speaker, he said. (The party's managing) bureau has recommended me.

(Additional reporting by Christian Lowe)

(Reporting by Oleg Shchedrov; writing by Christian Lowe and Oleg Shchedrov; editing by Robert Woodward)

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