A total of 34,612 people have died in drug-related killings in Mexico in the four years since President Felipe Calderón declared an offensive against cartels shortly after taking office, officials said tonight.

Killings reached their highest level in 2010, when there were 15,273 deaths, up from 9,616 the previous year.

At a meeting with anti-crime groups at which the government presented a data system to track drug-related crimes, Calderón said 2010 had been "a year of extreme violence".

The office of federal security spokesman, Alejandro Poire, said the four-year figure included 30,913 execution-style killings, 3,153 deaths in shootouts between gangs, and 546 deaths involving attacks on authorities.

Calderón said many of the killings in 2010 were generated by the turf war between the Zetas drug gang and their former allies in the Gulf cartel.

About half the killings took place in three northern states: Chihuahua, Sinaloa and Tamaulipas.

Poire said drug-related killings peaked in the third quarter of 2010 and declined by almost 11% in the fourth quarter.

Calderon said the decline towards the end of the year was important but refused to rule out another rise.

He said Mexico's 31 state governments must do more to deal with corruption in local police forces and to fight organised crime. The president said the federal government was doing its part, pointing to the recruitment of army troops to serve as state police officers in northern Nuevo León state, where killings have spiked this year.

Calderón's interior secretary, Francisco Blake Mora, presented a prototype of a national identity card, Mexico's first to be distributed to youths under 18 in some states. Most Mexicans currently use their voter ID cards as identification, but the new cards will have better security measures, including digital fingerprints and iris images, to prevent criminals from using false IDs.

In a separate development, the defence department said today that soldiers had caught Rigoberto Andrade Rentería, an alleged operations leader for the La Familia cartel, in the northern border city of Tijuana at the weekend. He was found with almost 60lb (27kg) of methamphetamine, it said.

The government had offered a reward of 5 million pesos (£263,000) for information leading to his arrest. La Familia cartel is based in the western state of Michoacán, but apparently has ties with traffickers in northern border states.