MEXICO CITY >> At least three women and six children in a prominent local Mormon family were killed Monday when their vehicles were ambushed in northern Mexico by gunmen believed to be members of organized crime, family members said. The attack alarmed a nation already reeling from record violence this year.

Members of the LeBarón family, dual Mexican and American citizens who have lived in a fundamentalist Mormon community in the border region for decades, were traveling in three separate vehicles when the gunmen attacked, several family members said. They described a terrifying scene in which one child was gunned down while running away, while others were trapped inside a burning car.

Two of the children killed were less than a year old, the family members said. Kenny LeBarón, a cousin of the women driving the vehicles, said in a telephone interview that he feared the death toll could grow higher.

“When you know there are babies tied in a car seat that are burning because of some twisted evil that’s in this world,” LeBarón said, “it’s just hard to cope with that.”

Mexico has suffered a string of violent episodes in the last month, each as devastating and infuriating for citizens as the last.

President Andrés Manuel López Obrador said during a morning news conference today that the region where the attack took place “has been a very violent area for many years.”

Alfonso Durazo, Mexico’s security minister, said today that “there were serious advances in the investigation” and that the women’s SUVs “could have been confused by the criminal groups that are fighting in the region.”

Among those groups is a cell that is linked to the Sinaloa Cartel, which was led by Joaquín Guzmán Loera, known as El Chapo. When security forces tried to arrest one of his sons last month in Culiacán, almost 400 cartel gunmen took control of the city and forced the government to withdraw.

Other groups are trying to take control of the region where the attack took place, Durazo said.

Fourteen police officers were killed in the state of Michoacán in the middle of last month, in an ambush stemming from violent clashes in the state. Days later, cartel gunmen laid siege to the city of Culiacán, in Sinaloa state.

In both cases, the stark challenges of public security were laid bare, raising questions about the government’s seriousness in combating the spiraling violence.

The president today defended his security strategy in the face of the drumbeat of violence and rising criticism that his government appears to be improvising against the power of criminal groups.

“You cannot put out fire with fire,” he said. “There will be intelligence, which has been lacking, more than force,” he said. “There will be prosecution, punishment. There will be a lot of attention to the population, especially for young people.”

But Monday’s brutal killings seem to have hit a new low, with infants, children and their mothers killed in broad daylight. It threatened to become a galvanizing moment for citizens fed up with the endless bloodshed and the government’s inability to do much about it.

President Donald Trump offered today via Twitter to help Mexico eradicate the cartels. “This is the time for Mexico, with the help of the United States, to wage WAR on the drug cartels and wipe them off the face of the earth. We merely await a call from your great new president!” he tweeted. “The cartels have become so large and powerful that you sometimes need an army to defeat an army!”

López Obrador said he would call Trump later today to thank him for his concern, but added that it was up to Mexico to deal with the matter.

“We appreciate and thank very much President Trump and any foreign government that wants to help, but in these cases we have to act with independence, according to our constitution and our tradition of independence and sovereignty,” López Obrador said.

Details of the attack remained murky early today, as state and local authorities struggled to determine the extent of the violence, and how exactly it unfolded.

It was unclear whether the attackers intentionally targeted the family, which has historically spoken out about the criminal groups that plague the northern border states of Sonora and Chihuahua, or whether it was a case of mistaken identity.

Claudia Pavlovich Arellano, governor of the state of Sonora, said that she would do everything in her power to ensure that the “monsters” who carried out the attacks did not go unpunished. “As a mother, I feel anger, revulsion and a profound pain for the cowardly acts in the mountains between Sonora and Chihuahua,” she wrote on Twitter.

Julian LeBarón, a cousin of the three women who were driving the vehicles, said in a telephone interview from Bavispe, Mexico, that the women and their children had been traveling from the state of Sonora to the state of Chihuahua.

His cousin Rhonita was traveling to Phoenix to pick up her husband, who works in North Dakota and was returning to celebrate the couple’s wedding anniversary. Her car broke down, LeBarón said, and the gunmen “opened fire on Rhonita and torched her car.”

She was killed, along with an 11-year-old boy, a 9-year-old girl and twins who were less than a year old, he said.

About 8 miles ahead, the two other cars were also attacked, killing the two other women, LeBarón said. A 4-year-old boy and a 6-year-old girl were also killed, he said.

Family members said several children were rescued, some having hidden by the roadside to escape the attackers.

“Six little kids were killed and seven made it out alive,” LeBarón said.

The women had married men from La Mora, which is in the municipality of Bavispe in Sonora. The surviving children were being taken by helicopter from Bavispe, the town closest to the La Mora community, to a hospital, he said.

He expressed bewilderment over what could have precipitated the attack. “They intentionally murdered those people,” LeBarón said. “We don’t know what their motives were.”

One of the women even got out of her car, LeBarón said, and put up her hands. “They shot her point blank in the chest,” he said.

LeBarón said the family had not received any threats, other than general warnings not to travel to Chihuahua, where they typically went to buy groceries and fuel.

As he watched the helicopter fly off with the injured children, LeBarón said that perhaps the killings would finally spur enough outrage to force change.

“We need the Mexican people to say at some point, we’ve had enough,” he said. “We need accountability; we don’t have that on any level.”

The family’s religious community is not affiliated with The Church of Jesus Christ of Latter-day Saints, the mainstream church with 16 million adherents that is headquartered in Utah.

Their community began in the early 20th century when members of the LeBarón family moved to Mexico and practiced polygamy, which was forbidden by The Church of Jesus Christ of Latter-day Saints. Religious communities that date themselves to Joseph Smith, the founder of The Church of Jesus Christ of Latter-day Saints, often call themselves Mormon. The mainstream church has abandoned the moniker. Polygamy has largely faded from the community.

It was not immediately clear if their religious beliefs were a factor in their deaths.

The massacre came a decade after two other members of the LeBarón family were kidnapped and killed after they confronted the drug gangs that exercise de facto control over the empty endless spaces of the borderlands south of Arizona.

A family member and other Mormons settled a town in Mexico in the 1940s; many of its residents speak English and have dual citizenship.

Kenny LeBarón said much of the family now lives in North Dakota, working in the oil fields and running their own businesses, but they frequently travel to the border area for holidays, vacations and other special events.

“We’re a huge family, but we’re very close,” he said.

Multiple family members posted a video, said to have been taken after the attack, showing a charred vehicle riddled with bullet holes, with smoke still rising from it.

Family members took to social media to implore the governments of Mexico and the United States to do something about the intensifying violence in Mexico, in particular in the areas along the country’s northern border, where Mormons and Mennonites have lived for decades despite the threat from rampant organized crime.

Many took particular aim at López Obrador, whose government has struggled to articulate a coherent security strategy even as homicides mount and organized crime groups have carried out increasingly brazen attacks both against citizens and the state.

In the aftermath of Monday’s attack, the government deployed the newly formed National Guard as well as the military to the area.