"If I have sufficient strength and health, if our people trust me in the future with such a position, then of course I do not rule such a turn of events," Medvedev said in an interview with Agence France-Presse and Le Figaro when asked if he had the ambition for another Kremlin term.

Medvedev, who on Monday embarks on a working visit to France, served as president after Putin stepped aside following the maximum two consecutive terms allowed by the constitution after his 2000-2008 stint.

But Putin, 60, stayed on as a powerful prime minister and Medvedev, 47, never fully emerged from the shadow of his fellow Saint Petersburg native, an impression strongly reinforced when Putin returned to the Kremlin in May 2012.

Medvedev, who in turn was then appointed prime minister in May, failed to bring about lasting change through a much-trumpeted modernisation programme in his one term as president.

But in his interview with AFP, he revealed he had not lost his political ambition.

"This (returning to the presidency) depends on a whole range of factors."

"Never say never, especially as I swam in that river once and this is a river that you can swim in twice," he said.

Russia will only go to the polls to vote for a president again in March 2018 and in the next half decade society is expected to see major change as the middle class grows and Internet use explodes. Putin has also not ruled out standing again.

This year's tightly choreographed job swap was criticised for being played out far from the public, and frustration over the return of Putin to the Kremlin fuelled the opposition protests that rocked Russia in the last year.

Some of Medvedev's supporters -- who saw him as a possible champion of a refreshed, innovative and more pro-Western Russia -- were hugely disappointed by his apparent surrender of the Kremlin back to Putin.

But Medvedev played up the tight links between the two men, saying he would find it impossible to work under anyone else.

"I would hardly have become prime minister under another president, I cannot imagine it at all," he said

"If there is someone you can work with comfortably as prime minister after being president it is just one person, Vladimir Putin."

However Medvedev has distanced himself from Putin on some issues, notably the case of feminist punk rockers Pussy Riot, two of whom have been sent to prison camps for performing a song against the Russian strongman in a church.

Reaffirming his belief that they should be released, he said: "I think they have already tasted what prison is... So further punishment in the form of prison is not necessary. This is my personal position."

On the case of Russia's best known prisoner, the former tycoon Mikhail Khodorkovsky, Medvedev said court decisions had to be respected but noted that the convict had never made a bid for clemency from the Kremlin.

Medvedev admitted that his modernisation drive had so far fallen short but expressed hope there was still time to put his ideas into place.

"It's true that for the moment modernization has not turned into a national idea and there has been no kind of radical progress reached."

"We need to modernize the economy but can you do this in 2-3 years? Of course not."