A Mexican army patrol was surrounded and attacked in the town of Altar, Sonora.
Altar, about 60 miles (100 kilometers) south of Sasabe, Arizona, has long been known as a staging ground for immigrant smuggling and is reportedly controlled by a faction of the Sinaloa cartel.
President Andrés Manuel López Obrador said that on Sunday soldiers had detained three criminal suspects, but were quickly surrounded by 10 or 15 pickups and 60 gunmen.
The assailants outnumbered the soldiers 10 to one, López Obrador said.
He said the assailants offered soldiers $500,000 to free one of the detained suspects, and when soldiers refused, a gunfight broke out and one soldier was killed.
Videos posted by Altar residents on social media showed a raging gunbattle, apparently including the sounds of automatic weapon fire.
Sonora Gov. Alfonso Durazo wrote in his social media accounts that four suspects had been detained for weapons possession.
Source: El Universal