Russian Prime Minister Vladimir Putin says he has accepted a proposal to stand for president next year.
Addressing the ruling United Russia party's annual congress, Mr Putin and current President Dmitry Medvedev backed one another to switch roles.
The announcements to the party, which Mr Putin leads, end speculation over which man would run for president.
The party dominates Russian politics and observers say Mr Putin's return to the Kremlin is now all but guaranteed.
He had already served two terms as president before Mr Medvedev took over in 2008. Mr Putin was barred by the constitution from standing for a third term.
"I want to thank you for the positive reaction to the proposal for me to stand for Russian president," Mr Putin said after Mr Medvedev suggested he should be a candidate.
"For me this is a great honour."
Earlier, Mr Putin told delegates that Mr Medvedev should head the party's list of candidates in December's parliamentary elections. Mr Medvedev accepted.
The congress must formally nominate the party's candidate - but that appears all but certain given the cheering and applause that greeted Mr Medvedev's proposal.
There have been months of speculation that Mr Putin plans to return to the Kremlin when elections are held in March.
Correspondents say most Russians believe he has greater influence in the country and far more power than Mr Medvedev.
9/24/11
Russia's Putin set to return as president in 2012
6:03 PM
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