Three women died and an 11-year-old girl was wounded in two separate attacks in the northern Mexican town of Balleza, the Chihuahua state Attorney General's Office said Friday.

In the first assault, eight gunmen in two vehicles opened fire Thursday on former Mayor Silvia Moreno, 56, and 50-year-old Cecilia Medina, the wife of another erstwhile mayor, in front of a church.

Minutes later, other assailants shot Francisca Villar and her daughter as they traveling in their car.

Villar was found dead inside the vehicle and the girl is in serious condition at a nearby hospital, the AG's office said in statement.

Shell casings from AK-47 assault rifles - the weapon of choice for Mexico's drug cartels - were found at both crime scenes.

Silvia Moreno was mayor of Balleza from 2004-2007. Her husband, Raul Fernandez, was gunned down outside the family's home in 1998 while running for mayor, and the couple's youngest child, 23-year-old Edwin Fernandez Moreno, was slain in January 2010.

Thursday's deadly shootings prompted a deployment of federal police and army troops to Balleza, a town at the far southern end of Chihuahua.

The state, which borders Texas, accounts for more than 11,000 of the roughly 40,000 deaths Mexico has suffered since December 2006 amid an increasingly vicious conflict pitting rival drug cartels against each other and the security forces.

Chihuahua's largest city, Ciudad Juarez, is Mexico's murder capital.

The gritty metropolis just across the Rio Grande from El Paso is the focal point of a turf battle between the Juarez and Sinaloa cartels.

Shortly after taking office in December 2006, President Felipe Calderon militarized the struggle against organized crime, eventually deploying 50,000 soldiers and 20,000 federal police to the worst trouble spots.

Yet, the 9,000 federal cops and troops on the ground in Chihuahua have had little impact on the level of violence.