It was unclear whether the attackers deliberately targeted the family, which has historically spoken of criminal gangs attacking the northern border states of Sonora and Chihuahua, or whether it was a mistaken identity.
Julian Lebaron, a cousin of the three women who drove the vehicles, said in a phone interview from Bavispe, Mexico, that the women and their children were traveling from Sonora to Chihuahua.
His cousin Ronita traveled to Phoenix to pick up her husband, who works in North Dakota, and returns to mark the couple's wedding anniversary. Her car broke down, Mr. Lebaron said, and the gunmen "opened fire on Ronita and started her car."
. miles ahead, the other two cars were also attacked, killing the other two women, Mr Lebaron said. A 4-year-old boy and a 6-year-old girl were also killed, he said.
Family members say several children have been rescued, some of them have fled by the road to escape from the attackers.
"Six young children were killed and seven made alive," says Mr Lebaron.
Women married men from La Mora, which is in the municipality of Bavispe in Sonora. The surviving children were taken by helicopter from the city of Bavispe, closest to the La Mora community, at a hospital, he said.