MOSCOW - Vladimir Putin accepted his ruling United Russia party's nomination on Sunday as its candidate in a March 4 presidential vote, paving the way for his return to the country's top office after four years as prime minister.

Russia's President Dmitry Medvedev (centre R) and Prime Minister Vladimir Putin (centre L) attend a United Russia party congress in Moscow Nov 27, 2011. [Photo/Agencies]

The timing of the announcement, which was a certainty after Putin revealed in September that he planned to return to the Kremlin next year, appeared aimed to give United Russia a boost in a parliamentary election next Sunday amid flagging support.

Putin accepted the nomination before it was even subject to a final vote at a United Russia congress also attended by President Dmitry Medvedev. Putin and Medvedev had announced plans to swap jobs next year at party meeting on Sept. 24.

That plan was met with mixed reactions among Russians, raising fears of increasing stagnation in the world's top energy producer and prompting complaints that Russia's political future had been determined behind closed doors.

Polls suggest Putin, president from 2000-2008, will win the presidency despite recent declines in approval ratings, but they show his party could lose its constitutional two-thirds majority in the State Duma lower parliament house in the Dec 4 election.