Three American Mother and atleast six of their children are killed.

At least three American mothers and six children from a Mormon community based in northern Mexico have been massacred in an attack blamed on drug cartel gunmen. Maria Rhonita Miller was killed along with her six-month-old twins, Titus and Tiana (left and right), her 10-year-old daughter Krystal (left) and 12-year-old son Howard (center)

Harrowing new details have emerged in the slaughter of three Mormon mothers and six of their children after cartel gunmen opened fire in a grisly ambush in Mexico on Monday.

Nine members of the LeBaron family were attacked eight miles apart on Monday while traveling in a convoy of three SUVS on a dirt road.

One hero mother died shielding her seven-month-old daughter who survived, it has since emerged. And a 13-year-old boy hid his siblings from gunmen in bushes and walked 13 miles for help, loved ones say.

Police confirmed they have arrested a suspected drug lord after the killings which left one vehicle torched and riddled with bullets.

The state prosecutor's office said one person was detained on Tuesday in the Mexican border state of Sonora and they were investigating whether they were involved in the massacre.

The mothers were driving in separate vehicles with their children from the La Mora religious community where they live, which is a decades-old settlement in Sonora state founded as part of an offshoot of The Church of Jesus Christ of Latter-day Saints.

Rhonita Miller and four of her children - her six-month-old twins, Titus and Tiana, her 10-year-old daughter Krystal and 12-year-old son Howard - were all killed.

Another two mothers, Dawna Langford and Christina Langford Johnson, as well as Dawna's sons, aged 11 and three, were also all killed.

Dawna's son Devin walked 13 miles to get help from relatives. He covered his injured siblings with branches before trying to make out where the shots were coming from to avoid the gunmen as he walked away.

Relatives say he reached the community six hours later. Family members alerted authorities before arming themselves with guns to go out searching for the injured children.

Christina saved her seven-month-old baby Faith's life by throwing the infant to the floor of their SUV as bullets tore through the vehicle.