In Mexico's crime capital Ciudad Juarez, which is just across the border from El Paso in the southern US state of Texas, gunmen opened fire on Saturday and killed three young students at a used car dealership.
A teenager, a woman and a 40-year-old man died in a second attack by unidentified gunmen elsewhere in Juarez, a statement from the Chihuahua state attorney general's office said yesterday.
A third triple homicide at a garage left a 13-year-old boy among the dead. Another three people were killed in separate shooting incidents in Ciudad Juarez, which has a population of 1.3 million and saw 2,900 murders last year.
Five men were also killed overnight in other parts of Chihuahua state, the official statement said. The northern Mexican state is among those worst hit by the bloody war between feuding drug cartels that has left over 34,200 people dead since December 2006, when President Felipe Calderon launched a nationwide crackdown that has failed to stem the tide of violence.
Separately, Mexican soldiers have shot dead 13 suspected gang members in the northeastern state of Tamaulipas, including six gunmen who were killed in a town near the US border, military officials said.
Three other suspected gang members were arrested during patrols over the past week. Tamaulipas has seen an escalation of violence recently between the rival Gulf and Zetas cartels as they vie for control of the lucrative trafficking routes to the United States.