In a stern address to a sombre crowd of senior Interior Ministry officers, Medvedev demanded police clean up corruption within their ranks and do a better job fighting crime.

He also laid into the law enforcement officers over killings and other scandals that have deepened Russians' distrust in the country's police force.

"The responsibility of Interior Ministry personnel at all levels must be increased," Medvedev said. "Violators of discipline must be fought - and fought firmly." Medvedev has made slimming the ranks of the 1.4 million-member Interior Ministry and fixing its deep-seated flaws a top priority, but faces formidable hurdles, including entrenched bureaucracy and limited resources.

The reform push will test the political mettle of Medvedev, - widely seen as No. 2 to Prime Minister Vladimir Putin - and the ability of Russia's ruling tandem to tackle the notorious bloated bureaucracy seen as a brake on economic growth.

Medvedev suggested police violence and corruption scandals over the past year have added to the urgency.

"A whole series of incidents in the Interior Ministry have resonated very strongly with our society and - I'll say frankly - affected the authority of the ministry and its personnel," Medvedev said.

Hours later, the Kremlin announced that Medvedev has dismissed two deputy interior ministers and 16 officers with the rank of general, most of them high-level provincial policemen.

Medvedev warned that the firings were "just the beginning of this work - more decisions will follow.”

He left Interior Minister Rashid Nurgaliyev in place and gave him a month to deliver a detailed plan to improve the ministry, including measures to properly vet potential recruits.

The speech came a day before a verdict was expected in the trial of a former Moscow precinct chief accused of killing at least two people in a supermarket shooting spree last April.

Medvedev said police convicted of crimes should face stiffer punishment than civilians - playing to public sentiment in a country where many see the police as a source of danger rather than protection.

He also ordered staff at the central Interior Ministry office cut in half, from nearly 20,000 to 10,000, and said several functions will be taken out of the ministry's hands.

Medvedev reiterated plans he announced in December to cut the size of the Interior Ministry by a fifth by Jan. 1, 2012, calling it "the beginning of a serious reform." Previous attempts at reform have failed and Kremlin opponents say Medvedev has made little or no progress on his pledges to fight corruption and improve the rule of law since Putin steered him into the presidency in 2008.

"In Russia, implementation is always a problem. We will have to see what is done and how," and Maria Lipman, a political analyst at the Carnegie Moscow Center.

She said the Kremlin could not fix the problems in the police force without easing the tight political control and centralized rule she said "breeds corruption and unaccountability." Medvedev warned police against trying to fudge crime-solving figures he said must be improved, saying the culprits in 2,000 murders and attempted murders has not been established.

At the same time, Medvedev peppered his comments with promises of better pay and better conditions for the police, saying increasing wages and benefits was a priority.