Russia's Vladimir Putin has formally accepted his ruling party's nomination to return to the presidency, in an address in which he warned the West against funding his political opponents.

Mr. Putin, who became prime minister in 2008 after two presidential terms, spoke Sunday in Moscow to a televised congress of his United Russia party. He accused unnamed foreign countries of bankrolling opposition efforts to influence the outcome of next week's parliamentary elections and presidential polls set for March.

Mr. Putin formally announced in September that he intended to reclaim the presidency next year in polls that analysts say he is certain to win. Under the deal, he will name current President Dmitry Medvedev as his prime minister.

The planned job swap has angered many in Russia, who say it would strengthen authoritarian trends and clear the way for Mr. Putin to become Russia's longest-serving leader since communist times.

If the 59-year-old Mr. Putin regains the presidency, he could serve two more six-year terms and remain in power until 2024.