YEKATERINBURG — Prime Minister Vladimir Putin warned on Thursday that the 2012 presidential election campaign would be dirty, but stopped short of saying whether he would seek another stint in the Kremlin. 

Putin made clear he would play a significant role in the election and told supporters he would need to cleanse politics after the campaign. 

"I shall go to wash, in the hygienic sense of the word but also in the political sense," Putin said, when asked at a regional conference of his ruling United Russia party what he would do the day after the March election. 

"After all the campaigns that we shall have to endure, you have to be properly hygienic. Unfortunately, this is an inevitable process," he said. 

Putin's remarks appeared aimed to portray the December State Duma elections and the presidential vote as hard-fought contests, contradicting critics who say government control of the levers of power means results are preordained. 

They also sounded like a warning to opponents of United Russia that they were in for a no-holds-barred battle. 

"As Churchill said: Democracy is the worst form of government but there is no better one," Putin said in Yekaterinburg. 

Putin and his protege, President Dmitry Medvedev, have indicated one of them, but not both, might run in the presidential election.