MOSCOW - Prime Minister Vladimir Putin accused the United States on Thursday of stirring up protests against his 12-year rule and said foreign countries were spending hundreds of millions of dollars to influence Russian elections.

In his first public remarks about daily demonstrations over allegations that Sunday's election was slanted to favour his ruling party, Putin said US Secretary of State Hillary Clinton had encouraged "mercenary" Kremlin foes by criticising the vote.

Russian Prime Minister Vladimir Putin speaks during a meeting in Moscow's White House Dec 8, 2011. [Photo/Agencies]

"She set the tone for some opposition activists, gave them a signal, they heard this signal and started active work," Putin told supporters as he laid out plans for his campaign to return to the presidency in a March election.  

"Pouring foreign money into electoral processes is particularly unacceptable," said Putin. "Hundreds of millions are being invested in this work. We need to work out forms of protection of our sovereignty, defence against interference from outside."  

He added: "We have to think of ways to tighten accountability for those who carry out the aims of foreign states to influence domestic political processes."

Anti-western rhetoric

Putin's remarks echoed the tough anti-Western rhetoric he employed in his 2000-2008 presidency to suggest Western nations were funding Kremlin critics to try to weaken Russia and prevent its resurgence after the collapse of the Soviet Union in 1991.

He has turned increasingly to the same tough talk since revealing in September that he planned to swap jobs with President Dmitry Medvedev next year.  

Accepting his United Russia party's nomination as a presidential candidate last month, he warned that the West would seek to influence the parliamentary and presidential votes.

"What is there to say? We are a big nuclear power and remain so. This raises certain concerns with our partners. They try t o shake us up so that we don't forget who is boss on our planet," Putin said.

The United States and the European Union have expressed concern about the conduct of the Russian election and the treatment of peaceful protesters. Clinton suggested on Tuesday that the vote was not free or fair.  

At a conference at NATO headquarters after Putin made his remarks, she said she had expressed "well-founded" concerns.

Voters bruised Putin in Sunday's election by reducing his party's majority in the lower house, undermining his mandate as he prepares to return to the Kremlin.

Putin remains Russia's most popular politician and could potentially have two more terms, ruling until 2024.  

But polls show his approval rating has fallen from previous heights, and the decline in support for his ruling party was a sign of frustration with the political system he has put in place, in which many Russians feel they have no influence.

About 5,000 people turned out on Monday night for the largest opposition protest in Moscow in years. Smaller protests have followed despite a police crackdown and former Soviet leader Mikhail Gorbachev called on Wednesday for a new election.