MEXICO CITY - At least 15 people were shot and killed and four others were wounded in an attack by suspected cartel gunmen at a bar in the northern Mexican city of Chihuahua, capital of the like-named state, authorities said.

‘Thus far the preliminary report is 13 dead and four wounded. The gender and ages of the victims are still unknown and the agents are investigating,’ Carlos Gonzalez, spokesman for the Chihuahua state Attorney General’s Office, told reporters.

The attack occurred when several armed assailants entered the El Colorado bar on the city’s north side and opened fire with automatic rifles, Gonzalez said. Chihuahua has been among the states hardest hit by violence pitting drug cartels fighting over smuggling routes to the United States.

On February 4, a shootout at a bar in that same city left nine people dead, including a police officer and five musicians, and 11 others wounded.

Over the past four years, the border state has accounted for nearly 30 per cent of the more than 50,000 drug-related homicides nationwide.

Many of the killings there have occurred in Ciudad Juarez, a sprawling metropolis across from El Paso, Texas, that is considered among the world’s deadliest cities.