Prime Minister Vladimir Putin on Thursday ruled out early presidential elections, saying the next presidential ballot in Russia would be held as scheduled in 2012.

"The next presidential election will take place in 2012.... For now, everyone must fulfil his duties in his place," Putin said, responding to a question on speculation he was planning an early return to the Kremlin.

Referring to President Dmitry Medvedev, Putin's hand-picked successor in the Kremlin, he added: "We have a very effective tandem. We have worked together for several years."

His comments came amid mounting speculation in Moscow political circles that Putin was determined to return to the Kremlin and that he wanted to do so as soon as possible -- well ahead of the next planned presidential elections.

That speculation was fuelled last month after a bill extending the presidential term to six years, was rushed through both houses of parliament last month. Its current, constitutional mandage is four years.

Because it would amend the constitution, the bill still has a legislative course to run -- most notably, it needs to be approved by legislatures in at least two-thirds of the Russian Federation's constituent subjects.

But most observers consider the outcome a foregone conclusion. Medvedev has said however that any lengthening of the presidential term would not apply to the term he is currently serving.