Sources tell CBS News that two U.S. ICE (Immigration and Customs Enforcement) agents were shot in the line of duty today approximately 100 miles outside Mexico City. One agent is in critical condition and the other is in stable condition, sources say.
One of the officers has died from his wounds, reports the Associated Press, quoting an anonymous official.
A U.S. Embassy spokesman in Mexico City tells CBS News the two agents were shot while driving from Mexico City to Monterey by unknown assailants.
"ICE is working with the U.S. State Department, Mexican authorities and other U.S. law enforcement partners to investigate the shooting. Our thoughts and prayers are with our colleagues," ICE officials said in a statement this afternoon.
Further details were unavailable at this time.
In December, U.S. Border Patrol agent Brian A. Terry was shot and killed just north of the Arizona-Mexico as he tried to catch bandits suspected of targeting illegal immigrants.
As CBS News reported last week, violence has been escalating in Mexican border towns. In Juarez, Mexico, nearly seven people a day have died this year.
Nationwide, almost 35,000 people have been killed in drug violence since President Felipe Calderon launched a military crackdown against drug trafficking shortly after taking office in December 2006.