FILE - President Donald Trump speaks to members of the media on the South Lawn of the White House, in Washington, Nov. 4, 2019.
FILE - President Donald Trump speaks to members of the media on the South Lawn of the White House, in Washington, Nov. 4, 2019.

WHITE HOUSE - U.S. President Donald Trump says Mexican drug cartels must be "wiped off the face of the Earth," after suspected gang members massacred nine U.S. women and children in northern Mexico.

The drug cartel members may have mistaken the victims' SUVs for those of a rival drug gang, Mexican officials said.

"If Mexico needs or requests help in cleaning out these monsters, the United States stands ready, willing & able to get involved and do the job quickly and effectively," Trump tweeted. He offered to help Mexico "wage war" against the cartels.

But Mexican President Andres Manuel Lopez Obrador rejected that approach, saying previous Mexican governments have tried a military solution and "it didn't work."

"The worst thing you can have is war," he said.

Lopez Obrador spoke with Trump by telephone on Tuesday.

"I thanked him for his willingness to support us, and informed him that the institutions of the government of Mexico will act to ensure justice is done," the Mexican president tweeted.

The ambush took place Monday in a remote area of Mexico's northern Sinaloa state, where the Sinaloa cartel has carried a long and bloody turf war with rival drug gangs.

The Agency for Criminal Investigation in Sonora said Tuesday that authorities detained one person in the Agua Prieta area who was holding two people gagged and tied up in a pickup truck along with multiple guns and ammunition.  Investigators are working to determine if the person was involved in the killings.

The victims are members of the LeBaron family, U.S. citizens who formed a fundamentalist Mormon community decades ago in the border region.

WATCH: Drug cartel crime

The family was traveling in three separate vehicles and were heading to visit relatives. One woman was driving to meet her husband at the airport in Phoenix, Arizona, across the U.S. border.

When the gunmen opened fire, some of the children fled. One woman jumped out of the car and waved her hands to plead with the gunmen that they are unarmed and innocent. She was shot down in cold blood.

Mexico's President Andres Manuel Lopez Obrador shows a map of the area where members of a U.S. Mormon family were killed near the U.S. border, at the National Palace in Mexico City, Mexico, Nov. 5, 2019. (Presidential Press Office)

Some of the bullets struck one of the cars, causing the gas tank to explode, incinerating a woman and four children, including 8-month-old twins.

Some children managed to escape and hide, despite gunshot wounds. Mexican authorities found them and brought them to nearby hospitals.

Although Mexican authorities say the family were likely victims of mistaken identity, family members say the gunmen knew exactly who they were targeting.

The LeBaron family has been in conflict with drug gangs for years. Benjamin LeBaron, who had taken on the gangs, was murdered in 2009, and several other members of the Mormon community in Chihuahua have also been targeted by drug traffickers.

The burnt wreckage of a car that transported a Mormon family is seen in Bavispe, Sonora, Mexico, Nov. 4, 2019, in this picture obtained from social media. (Credit: Kenneth Miller/Lafe Langford Jr.)

“Members of the Church of Jesus Christ of Latter-day Saints from the Utah territory originally went into Mexico in the 1880s at the height of a federal government crackdown on polygamy,” according to University of Utah’s Mormon Studies professor W. Paul Reeve.

In recent years, Mormons in the area were targets of kidnappings, and two members of the Chihuahua Mormon community, including a LeBaron family member, were killed in 2010 in an apparent revenge attack after security forces tracked down drug gang members.

“It’s not a safe place, but it is their home,” Wilson told VOA. “They were there before the security situation deteriorated. They are living in a part of rural Mexico that is under dispute by criminal organizations” near the U.S. border with its important trafficking corridors.

Former U.S. ambassador to Mexico Roberta Jacobsen told MSNBC that innocent parties are commonly killed by cartel gunmen. 

“The reaction from cartel members is frequently to shoot first and ask questions later about who is involved,” Jacobsen said.