A Chihuahua state police major was gunned down over the weekend as he was leaving a bar in Ciudad Juarez, a border city in northern Mexico, state officials said.

The officer was leaving the bar early Sunday in downtown Ciudad Juarez, located across the Rio Grande from El Paso, Texas, when he was stopped by at least two men who opened fire on him, state police spokesman Carlos Gonzalez told Efe.

Investigators are trying to determine whether the officer was off duty or working.

Officials did not identify the slain officer, but some media outlets reported that he was Carlos Rodolgo Guereque, who commanded a unit in the Chihuahua state Attorney General's Office and was in charge of investigations in Ciudad Juarez.

Chihuahua has accounted for nearly 30 percent of the more than 50,000 murders committed in Mexico in the past four years, with most of the killings occurring in Ciudad Juarez.

Ciudad Juarez first gained notoriety in the early 1990s, when young women began to disappear in the area.

More than 500 women have been killed in Ciudad Juarez since 1993, according to the National Human Rights Commission, with the majority of the cases going unsolved.

Ciudad Juarez has been plagued by drug-related violence for years and held the dubious distinction of being Mexico's murder capital in recent years.

The Juarez cartel has been battling the rival Sinaloa cartel for control of smuggling routes from Ciudad Juarez into the United States.

The border city, which topped the list of the world's deadliest cities for three consecutive years, dropped to second place last year with 148 homicides for every 100,000 residents.

The murder rate took off in the border city of 1.5 million people in 2007, when 310 people were killed, then it more than tripled to 1,607 in 2008, according to Chihuahua AG's office figures, with the number of killings climbing to 2,754 in 2009.

More than 3,100 people were murdered in the border city in 2010, making it the worst year since the cartel turf war sent the homicide rate skyrocketing in 2008.

Nearly 2,000 people were murdered in Juarez in 2011.

Juarez registered 653 murders in the first six months of this year, down from 1,322 in the same period last year, the Chihuahua AG's office said.

The federal government recently released statistics showing that murders were down 70 percent in Juarez compared with two years ago. EFE