The report comes a day after Eduardo Medina Mora, Mexico's attorney general, said that 6,290 people were killed last year in drugs violence, double the toll for 2007, and that more than 1,000 had already been killed in 2009.

Calderon himself also angrily denied claims on Thursday that Mexico had become a "failed state" due to the escalating violence after US concerns that Mexico was losing control of its territory to drug cartels and allowing violence to spiral out of control.

"To say that Mexico is a failed state is absolutely false," he told the Associated Press news agency.

"I have not lost any part - any single part - of the Mexican territory."

US arrests

Mexico also promised to deploy more troops into the northern border city of Ciudad Juarez, at the heart of the country's drug war, Fernando Gomez Mont, the interior minister said earlier this week.

Ciudad Juarez, across from El Paso, Texas, has become Mexico's most violent city as security forces take on drug cartels fighting for control of smuggling routes into the US.

The US Drug Enforcement Administration (DEA) arrested 52 alleged members of Mexico's Sinaloa cartel on Tuesday and Wednesday in the states of California, Maryland and Minnesota as part of what it calls Operation XCellerator.

In all the operation led to the arrests of 750 people over a 21-month period, US officials said.

Most of the violence is attributed to a bloody battle between the Ciudad Juarez and Sinaloa drug cartels over lucrative smuggling routes into the US.