MOSCOW — The longtime aide tapped by Vladimir Putin to be his successor as president of Russia declared on Tuesday that he wanted Putin to be his prime minister, offering the clearest indication yet of how Putin plans to maintain firm control over the Kremlin after his term ends in March.

The announcement, in a speech to the nation by the aide, Dmitri A. Medvedev, raised the prospect of a stark realignment in the structure of the Russian government, which currently is led by a strong president who appoints a prime minister to serve largely as an administrator.

As prime minister, Putin could overshadow Medvedev, turning him into the kind of figurehead president found in parliamentary systems like Germany's or Italy's.

Putin did not publicly respond to Medvedev's offer. But it is widely assumed here that Medvedev was taking this step at the behest of his patron.

Some senior Kremlin officials noted that Putin had said in October that he would remain an influential figure after his term ended, possibly by moving to the prime minister's office. Putin is barred by the constitution from running for a third consecutive term.

Beyond offering Putin the position, Medvedev, a longtime protege of Putin who has no other source of support in the Kremlin, did not elaborate on his vision for a Putin premiership.

In his speech, Medvedev praised Putin and said Russia must continue the course that the president has followed since taking office in 2000. To do so, Medvedev said, Putin needed to remain in the government.

"It is not enough to elect a new president who shares this ideology," Medvedev said. "It is not less important to maintain the efficiency of the team formed by the incumbent president. That is why I find it extremely important for our country to keep Vladimir Vladimirovich Putin at the most important position in the executive power, at the post of the chairman of the government."

Medvedev also echoed Putin's comments in recent months praising Russia's revival on the world stage. "The attitude toward Russia in the world is different now," he said. "We are not being lectured like schoolchildren; we are respected and we are deferred to. Russia has reclaimed its proper place in the world community. Russia has become a different country, stronger and more prosperous."