The murder rate since Mexican President Felipe Calderón cracked down on violent drug cartels four years ago has topped 30,000.
Even as the government has claimed that it has "systematically weakened" La Familia drug cartel in western Mexico, it reported that about 12,500 people were killed through November this year. By comparison, there were 9,600 gangland murders in all of 2009.
Authorities have also confiscated illegal drugs with a street value of more than $11 billion during Calderon's campaign.
In a joint statement, Attorney General Arturo Chávez Chávez and the army, federal police and navy said La Familia cartel was reeling from the recent deaths or arrests of some of it leaders. The government claims to have captured or killed 10 of the estimated 24 reputed kingpins on its most-wanted list.
The statement said the cartel had begun to pursue false propaganda campaigns depicting itself as a protector of inhabitants of the western state of Michoacán. Indeed, residents sympathetic to the group have organized rallies and marches earlier this month in its support.
"The systematic weakening of this criminal group due to the actions of the federal government has forced some of its members to adopt false rhetoric about helping the people of Michoacán, when in fact their operational methods are to terrorize and rob them," according to the statement.
That was an apparent reference to a Dec. 9 recording by La Familia leader Servando Gómez, who urged cartel supporters over a radio frequency to continue fighting, hours after the death of the group's leader, Nazario Moreno, nicknamed "The Craziest One" or "The Doctor."
"God is with us, onward to victory!" Gómez is heard saying in the tape, in which he urged cartel supporters to join recent demonstrations calling for the withdrawal of federal police and the army.
Gómez is also heard complaining that the government had not accepted the cartel's offer to declare a temporary truce.
In its statement, the federal government stressed it would not negotiate with cartels.
"The only option that remains for these criminals to hand themselves over to the authorities," it said.
The statement also stressed that federal forces are in Michoacán largely because local and state police are unable to handle the fight against the cartel. It noted that only 15 percent of state police officers and only 9 percent of municipal officers in Michoacán had been vetted or subject to background checks.
Many local police forces have been accused of collaborating with drug gangs.
Also Thursday, the navy reported it has seized 240 200-liter (53 gallon) drums of a precursor chemical used to make methamphetamines. It said the shipment was seized Thursday at the Gulf coast port of Altamira.
Based on reporting by the Associated Press. EFE contributed to this story.