Calderon has sent thousands of troops to states on the US border and other areas in the country where drugs cartels operate.
 
But despite the campaign, violent attacks and execution-style killings have continued.
 
Funded by money from the drugs trade, gangs are known to have bribed poorly paid police officers and regularly out-gun local police by using assault rifles and grenade launchers.
 
Drug-related violence has lead to 700 deaths in Mexico so far this year.
 
On Thursday, gunmen attacked the police chief of Cancun, killing one of his bodyguards although the police chief himself escaped unharmed.
 
Earlier in the week, masked gunmen killed five soldiers in a shootout in the western state of Michoacan.
 
Local police officers have occasionally been assassinated by gangs, although it can be unclear whether they are targeted because of their own involvement with organised criminals or in retribution for trying to catch them.