MEXICO CITY – At least four people were killed Thursday during a gunbattle in the northern Mexican city of Chihuahua, officials told Efe.

Two of the fatalities may have been officers of the federal highway police, a spokesman for the Chihuahua state Attorney General’s Office said. National law enforcement authorities have not commented on the identity of the victims.

Municipal police cordoned off the scene as federal agents began the investigation.

It appeared likely that gunmen working for one of Mexico’s powerful drug cartels were involved in the confrontation. The state of Chihuahua has accounted for 1,200, or 40 percent, of the 3,000 gangland murders reported nationwide so far in 2009, press tallies indicate.

Mexico has been plagued in recent years by drug-related violence, with powerful cartels battling each other and the security forces, as rival gangs vie for control of lucrative smuggling and distribution routes.

Armed groups linked to the cartels murdered around 1,500 people in 2006 and 2,700 people in 2007, with the 2008 death toll soaring to more than 6,000. EFE