Ciudad Juarez, Mexico (CNN) -- At least five men were killed when attackers wielding assault rifles raided a bar in this violence-plagued Mexican border city over the weekend, authorities said.
At least nine others were injured during the attack, which occurred early Sunday morning after people had packed the "Desesperados" bar to watch the Manny Paquiao-Anotonio Margarito boxing match, Chihuahua state prosecutors said.
Witnesses told investigators that several of the alleged assailants guarded the bar's doors while others entered to locate their targets.
The victims ranged in ages from 30 to 35, prosecutors said.
Ciudad Juarez, Mexico's most violent city, shares a border with El Paso, Texas.
There have been more than 2,500 drug-related deaths reported there this year.
Nationwide, more than 28,000 people have died in drug violence since December 2006, when Mexican President Felipe Calderon took office and started his stepped-up campaign against organized crime.