Herosillo - Mexican authorities say at least four men died in a series of shootouts in the city of Agua Prieta, across the border from Douglas, Arizona.
Sonora state police said in a statement on Saturday that two groups of criminals clashed before dawn in several of the city's neighbourhoods. At least three bystanders were wounded.
The statement said that three of the dead men are from the neighbouring state of Sinaloa and that the fourth victim has not been identified.
Police found the bodies scattered throughout Agua Prieta.
Authorities didn't say what groups participated in the firefights but the area has seen an increase in violence as the Sinaloa and Zetas drug cartels fight over turf.