MOSCOW -- Vladimir Putin assured his political party Monday that Russia's age of Putin is far from over, pledging to accept an offer of the prime minister's post when he leaves the presidency next year.

Putin, whose power still seems ascendant, finally settled on one of his many post-presidential political options, which had ranged from altering the Russian constitution so he could run again to outright retirement.

The Russian president has pledged to accept a job that is, at least on paper, a demotion -- perhaps confident of the power conferred by his enormous popularity and by the loyalty of the fellow KGB veterans he placed in many of the Kremlin's most important jobs.

Putin, 55, presented his decision in a speech to leaders of the United Russia party, shortly before they voted to nominate the president's longtime protege, First Deputy Prime Minister Dmitry Medvedev, as their candidate in the March 2 presidential contest.

With the support of Putin and the Kremlin's tight control over the nation's media and political landscape, Medvedev appears certain to win.

After Putin endorsed Medvedev's presidential bid last week, the 42-year-old St. Petersburg-educated lawyer urged Putin to serve as his prime minister if he is elected. Putin waited a week before responding.

Many believe Putin would remain the real leader of Russia, whatever his title. But he pledged not to undermine his successor by strengthening the prime minister's job and weakening Russia's strong presidential system.