CIUDAD JUAREZ, Mexico -- Three bystanders died in the crossfire of a shootout between gunmen, police and soldiers in northern Mexico on Sunday.
The victims were a 14-year-old boy and two women aged 18 and 47, according to a statement by the prosecutors' office in northern Coahuila state.
The statement said gunmen traveling in two vehicles opened fire on a convoy of federal police and soldiers in the city of Saltillo, Coahuila. The officers and soldiers returned fire.
It was not clear who fired the shots that killed the bystanders, but the state attorney general's office said it was investigating and expressed condolences to the victims' families.
"They are civilians who unfortunately died in the exchange of gunfire," it said, describing a running series of confrontations between police and assailants who allegedly fired shots into the air to clear bystanders from their path at one point.
Three gunmen also died Sunday in a separate shootout in another Coahuila city, Torreon.
Coahuila has been the scene of bloody turf battles between the Sinaloa cartel and the Zetas drug gang.
Mexico's army, which has taken a leading role in combating drug gangs, has come under criticism for alleged indiscriminate use of force and firing on civilians.
In the border city of Ciudad Juarez, meanwhile, the death toll from a birthday party massacre late Friday rose to 14 after an 18-year-old male died of his wounds.
Nineteen people were wounded in the attack on two private homes where about four dozen partygoers had gathered for a teen's birthday.
The dead identified so far were 13 to 32 years old, and the majority of the victims were high school students, a survivor said.
While investigators said they have not yet identified the perpetrators or a motive, police found 70 bullet casings from assault weapons typically used by drug gangs at the scene of the shootings. Cartel violence has killed more than 2,000 people so far this year in the city across from El Paso, Texas.
Friday's attack recalled a similar massacre in Ciudad Juarez in January, when gunmen killed 15 people at a house party.