The Mexican Government says that the increased killings are often the result of leaderless drug gangs turning on each other for the fewer spoils that remain.
But some analysts fear that by taking on the drug runners, President Calderon has unleashed forces he arguably will not be able to control.
There is plenty of evidence that Mexican law enforcement agencies have been extensively infiltrated by the cartels.
The government is having to rely on the army to police parts of the country.
Mr Calderon says his war on drugs will be long and difficult. In that, he is being proved right, our correspondent says.