President Vladimir Putin's choice for prime minister said Thursday that he would not rule out a run for the presidency, adding to the intrigue following his surprise nomination just months before elections.

Putin nominated Viktor Zubkov on Wednesday after dismissing Mikhail Fradkov, who had headed the Cabinet since 2004. The State Duma, the loyal lower parliament house that often acts as a rubber stamp for Kremlin policies, is expected to approve the choice Friday.

Asked whether he would be president, Zubkov said: "If I achieve something in this position, I do not rule out this scenario."

Zubkov's remark deepened the uncertainty Putin created by choosing his little-known ally to replace Fradkov ahead of December parliamentary elections and a March presidential vote in which Putin is barred from seeking a third straight term.

Zubkov, who turns 66 on Saturday, has spent the last six years overseeing investigations into suspicious financial transactions as the head of the agency charged with fighting money-laundering. He was widely praised by members of the dominant pro-Kremlin party United Russia after his nomination was announced.

But while his confirmation is a foregone conclusion, Putin's nomination of a virtual unknown ahead of crucial elections muddied Russia's political waters, amplifying questions about the popular leader's plan for his country and himself.

Putin said Wednesday that he needed to appoint a government better suited to the campaigns for December Duma elections and the March presidential vote, in which he is constitutionally barred from seeking a third straight term, and to "prepare the country" for life after the elections.

The nomination ignited speculation over Zubkov's role: whether he is Putin's favored successor or a caretaker prime minister, perhaps to be replaced closer to the presidential vote.

Some saw his appointment as signaling Putin's intention to retain control over the country even after he steps down, and others speculated that his caretaker role could extend into the presidency, allowing Putin to return in 2012 or sooner.

Putin has strongly suggested that he plans to retain some measure of influence after he leaves office, and has not ruled out a presidential bid in 2012.

"Zubkov is 65. If he does become Putin's successor, it will likely be for only one term. Then Putin will say, 'I am ready to return to the presidency,'" Communist lawmaker Viktor Ilyukhin said on Ekho Moskvy radio.

Zubkov's remark to reporters about the presidency came during a day of closed-door discussions with lawmakers in the State Duma, the lower parliament house, before the vote expected Friday on his confirmation, which is assured.

Communist Party leader Gennady Zyuganov said his faction, with more than 50 votes, would vote against Zubkov. But a simple majority of 226 votes in the 450-seat chamber is sufficient for approval, and United Russia has about 300 seats. Flamboyant ultranationalist Vladimir Zhirinovsky, whose party backs most Kremlin initiatives, said it would support Zubkov.

In Washington, State Department spokesman Sean McCormack said Wednesday that the United States is confident it can work with the new prime minister.

In terms of "the development of Russian democracy, we've made known in public, quite clearly, our views about that, some of our concerns about it," he said.

"The upcoming elections we hope will take place in a climate that is free, fair and transparent. That means not just on election day, but in the run-up to election day. I don't detect that today's events will affect that one way or the other."