Updated

Seven men were shot to death in an apparent ambush by rival drug traffickers near the Mexico-Arizona border, authorities said Thursday.

An eighth man was found wounded on a hill in an area called Ejido Los Ejemplos near Sonoyta, Mexico, Sonora state police said in a statement. Sonoyta is close to the U.S. border crossing at Lukeville, Arizona.

The bullet-riddled bodies were found inside a pickup truck Wednesday night, authorities said.

Sonoran police said the survivor of the Tuesday attack told investigators that he and the other men had just dropped off marijuana when gunmen opened fire with automatic rifles on their pickup truck.

All of the men are believed to have been from the state of Sinaloa, home of the drug cartel by the same name.