Gunmen killed two girls, ages 15 and 16, in Ciudad Juarez, a border city in northern Mexico, police said.
The gunmen entered a house Saturday in the southern section of Ciudad Juarez, located across the border from El Paso, Texas, and killed the teenagers, municipal police spokesmen told Efe.
One body was found on the second floor and the other on the first floor.
The victims have not been identified and police have not determined the motive for the killings.
Ciudad Juarez, Mexico’s murder capital, first gained notoriety in the early 1990s when young women began to disappear in the area.
In most of the slayings, the victims were young women from poor families who came to the border city from all over Mexico to work in the many assembly plants, known as “maquiladoras,” built there to take advantage of the North American Free Trade Agreement.
Investigators have not determined who is behind the killings, although there has been speculation that serial killers, organized crime groups, people traffickers, drug smugglers and child pornographers, among others, may be involved.
More than 500 women have been killed in Juarez since 1993, with the majority of the cases going unsolved.
The latest killings occurred hours after President Felipe Calderon visited the area and met with federal, Chihuahua state and municipal officials.
Federal officials announced at the start of the weekend that the murder rate in Juarez had fallen sharply over the past six months from an average of 11 people a day in October 2010 to four per day in April.
The decline in the murder rate is due to cooperation among the federal, state and local governments, and the deployment of 5,000 Federal Police officers to Juarez since last April, federal security spokesman Alejandro Poire said.
Not only has the homicide rate dropped in Juarez, where there have been 8,500 drug-related deaths in the past four-and-a-half years, but officials also have made progress in combating other crimes as well during that six-month period, Poire said.
All of the criminal organizations active in Ciudad Juarez – a city of 1.2 million people – are being “weakened,” Poire said.
The violence in Ciudad Juarez is blamed on a brutal war for control of the border city being waged by the Juarez and Sinaloa cartels with backing from hit men from local street gangs.
Army soldiers also have played a role in restoring security, seizing 2,000 weapons, 150,000 rounds of ammunition, 70 tons of marijuana, more than 400,000 psychotropic pills and 112 vehicles between March 2008 and May 2011, Poire said.
The army captured 1,400 suspects during that period, the federal security spokesman said, adding that since 2007 a total of 3.3 billion pesos ($284 million) has been invested in security, education, culture, health and social development.
Ciudad Juarez will be the destination next month of an anti-violence march headed by poet and activist Javier Sicilia, who has launched a movement aimed at sharply reducing the violence resulting from turf wars among rival drug cartels in numerous states and a government offensive against the gangs.
Sicilia, whose son was killed earlier this year by suspected cartel gunmen, is calling for Calderon’s “militarist strategy” to be replaced by a citizen safety initiative.
Calderon’s critics contend that his strategy has only triggered an increasingly violent response from drug traffickers, who are known for brutal tactics such as hanging their decapitated rivals from bridges in urban areas.
Federal forces also have been accused of rights violations, but the government says it is essential that they play the lead role in combating the cartels due to widespread corruption among law enforcement at the local and state level.
Conflicts among rival drug cartels and between criminals and the security forces have claimed 40,000 lives in Mexico since December 2006, when Calderon militarized the struggle against the drug trade shortly after taking office.