November was the bloodiest month to date with 943 murders
Drug-related murders in Mexico more than doubled this year to nearly 5,400 and the violence is likely to worsen in 2009, the nation's top prosecutor says.
"We still haven't reached the peak of violence," Attorney General Eduardo Medina Mora told reporters.
He attributed the rising violence to the internal power struggles as drug gangs split and fight for turf.
The government has deployed some 40,000 troops and police since December 2006 against the cartels.
The number of killings linked to organised crime registered between 1 January and 2 December was 5,376 - a rise of 117% on the same period last year, Mr Medina Mora told foreign correspondents in Mexico City.
November was the bloodiest month yet - with 943 murders.
"We're still seeing the curve rise. We still haven't reached the peak of violence," Mr Medina Mora said.
But he stressed that Mexico's overall murder rate per 100,000 inhabitants is 11, compared with 33 in Colombia or 50 in El Salvador.
The attorney general said the wave of killings began in January when the powerful Sinaloa cartel split into factions, setting off a bloody turf war.
Much of the violence has been in the northern states of Baja California, Sinaloa and Chihuahua where the Sinaloa cartel, led by Mexico's most-wanted man, Joaquin "Shorty" Guzman, fights with his rival Vicente Carrillo over smuggling routes into the US.
Mexican authorities say the violence shows the gangs are being hit hard
But other parts of the country have not been immune. Authorities in the southern state of Guerrero said at least 18 people had been killed in a single day at the weekend, the Associated Press reports.
The heads of two of the victims were left in plastic buckets outside a college in the state capital, Chilpancingo.
Officials say the gruesome violence shows that the drugs gangs are being squeezed, intensifying their internal squabbles.
But the fight against organised crime has been hit by a series of corruption scandals in recent months, with more than a dozen high-ranking police officers and prosecutors detained or charged for allegedly passing information to the cartels.
Police officers have also been the targets of kidnappings and killings.
Last week, the US government released $197m (£133m) to help Mexico fight the drugs cartels.
It was the first part of the Merida Initiative, a $400m (£270m) scheme to assist Mexico's efforts to take on the drugs trade.
Ninety percent of all the cocaine consumed in the US is believed to reach the country via Mexico.
Mexican President Felipe Calderon has long sought, and been promised, financial aid from Washington to try to defeat the traffickers.