Federal agents in Torreon, Mexico

Federal police in the north Mexican city of Torreon were attacked by gunmen twice in one day this week, bringing the total number of these targeted attacks to 11 since October.

Around midday on November 21, an armed group opened fire on a federal police patrol on the outskirts of Torreon, reported Milenio. The attack, which injured one officer, prompted authorities to activate a "Code Red," deploying more federal personnel to find the attackers.

A little under five hours later, a federal police unit was attacked outside a hotel in Torreon, with gunmen injuring four officers, according to Milenio. As with the earlier attack, the assailants escaped.

No information has been offered on who is responsible for the attacks. The two incidents bring the total of targeted assaults against the federal police to 11 since October 16, with two officers killed, reported Vanguardia.

InSight Crime Analysis

Torreon has become one of Mexico's most violent cities in recent years, and is now second only to Acapulco in terms of annual homicide rate. Much of this spike in violence is down to the arrival of the Zetas gang in the city in 2007 and their battle for control against the rival Sinaloa Cartel. In 2006, there were only 62 registered homicides in Greater Torreon; last year there were 990, according to a Reuters report.

Whether the spate of attacks on federal agents has been carried out by one group is unclear. However, it is a sign that criminal organizations in the area feel confident to target the federal authorities, something they would normally refrain from doing in order to avoid drawing attention to their criminal operations.