LOS ANGELES, CA (Catholic Online) - The seven attacks took place in Guadalajara in a two-hour period this week. The attacks appear to have been coordinated by drug gangs, possibly in retaliation for the arrests of their members.

According to Fernando Guzman Perez, interior secretary of Jalisco state, a policeman and two transportation workers were injured in the attacks. "This is an orchestrated attack by criminal forces," Perez said.

"There have been arrests ... of people linked to these cells of organized crime, and perhaps it was because of those detentions that attacks over the past few hours broke out."

Assailants hurled a grenade at a police station and burned a bus and commuter trains to block streets, injuring transportation workers.

Other attacks took place in the northern cities of Monterrey and Zacatecas, resulting in several deaths.

In the wealthy Monterrey suburb of San Pedro Garza Garcia, attackers fired upon a group of Mexican marines who were responding to reports of illicit activity at an apartment complex. The marines returned fire, killing four suspected attackers, the navy said.

In addition, a series of attacks in Monterrey left a federal police officer and three suspected cartel members dead and three police officers injured.

The suspected cartel members erected roadblocks to aid their escape, and hurled a grenade at a police checkpoint that caused a patrol car to explode. In one of the assaults, attackers driving a black 4WD vehicle opened fire on police officers in a patrol car in the suburb of Monterrey Apodaca, killing one and wounding three.

January was the bloodiest month of drug violence in recent history in Monterrey. According to public security office figures, more than 120 people were killed as a result of organized crime, including 21 police officers.