Three mothers and at least six children with Utah ties were killed Monday in Mexico, according to the victims’ families.

The victims are U.S. citizens who have lived in a fundamentalist Mormon community in the border region for decades. They 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.

Three other children suffered bullet wounds but survived, said Lafe Langford Jr., a relative of some of the victims. He said doctors from across the Mexican state of Sonora were coming to help.

Video posted online by family early Tuesday showed what was described as a helicopter flying five children to Douglas, Ariz., for medical treatment.

🙏 The Helicopter with five children headed to US hospitals After being shot and their mother’s killed What an unbelievable day of shock and tears🙏🙏

Posted by Willie Jessop on Monday, November 4, 2019

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.”

The crimes set off a wave of social media posts from the victims’ families expressing sorrow at the deaths and pleas for the return of those who had earlier been kidnapped.

Maria Rhonita Miller and four of her children died on a road in northern Mexico, according to Langford and social media posts. Miller was traveling to Phoenix to pick up her husband, who works in North Dakota and was returning to celebrate the couple’s wedding anniversary, said her cousin, Kenny LeBarón.

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.

¡OJO! Atención a todo el mundo!!! Somos una comunidad de ciudadanos con doble nacionalidades, paisanos y estadounidenses, que viven y operan entre México y los Estados Unidos. Estamos bajo ataque mientras hablamos por los carteles en México ... Hemos estado solicitando a las embajadas estadounidenses en México todo el día sin resultado ... ¡Necesitamos que se compartan esto y que todo el mundo sea testigo de los atroces actos inhumanos y bárbaros que se cometieron contra nosotros hoy! Rhonita Miller y sus 4 hijos fueron asesinados a tiros en este vehículo y en este mismo momento hay DOS más Suburban con 2 de nuestras familias, con un total de 2 esposas y 10 niños desaparecidos y / o secuestrados por el cartel ... ¡Necesitamos ayuda de inmediato! .. ¡Ayudenos!

Posted by Lafe Langford Jr on Monday, November 4, 2019

About 8 miles ahead, the two other cars were also attacked, killing the two other women, LeBarón said. The bodies of Dawna Ray Langford, 43, and Christina Marie Langford, 31, were found later Monday, Lafe Langford Jr. said.

The bodies of two of Dawna Ray Langford’s children, Trevor, 11, and Rogan, 3, also were recovered Monday. An earlier report said Christina Marie Langford’s baby daughter, Faith Marie Johnson, had died, too, but that turned out to be incorrect.

Julian LeBarón said in a telephone interview from Bavispe, Mexico, with The New York Times that the women and their children had been traveling from the state of Sonora to the state of Chihuahua.

Social media posts from family of the victims said at least one of the children walked from the ambush site to the family home. Other children were found on the side of the road where the attackers abandoned them.

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

The families are from La Mora, about 70 miles south of Douglas, Ariz. They are a mix of people who worship with the mainstream, Salt Lake City-based Church of Jesus Christ of Latter-day Saints and polygamous offshoots. Lafe Langford Jr. said the killings happened near the town of Bavispe in the state of Sonora. The gunmen, Langford said, are believed to be members of a cartel from Chihuahua who encroached on another cartel’s territory.

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.

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, particularly 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 President Andrés Manuel 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 against citizens and the state.

On Tuesday morning, U.S. President Donald Trump tweeted: “A wonderful family and friends from Utah got caught between two vicious drug cartels, who were shooting at each other, with the result being many great American people killed, including young children, and some missing. 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. The great new President of Mexico has made this a big issue, but the cartels have become so large and powerful that you sometimes need an army to defeat an army!”

Trump offered Mexico help against the violence on Tuesday.

Sen. Mitt Romney, R-Utah, offered condolences on behalf of himself and his wife.

“Ann and I are heartbroken for the victims of the horrific attacks in Mexico," Romney wrote. "Our prayers are with their families who have suffered such an unspeakable tragedy. The U.S. must work with Mexican officials to hold accountable those responsible for this senseless violence.”

A video posted by Miller’s father-in-law and posted to Facebook showed the remains of the family’s Chevy Suburban. It had been burned and was still smoldering. Bullet holes are visible in the paneling.

Map locates the site of the cartel killings of at least nine US citizens in the Mexican state of Sonoma;

The accompanying text says the Millers were ambushed. Langford, in a phone interview, said it appears the gunman mistook the Miller and Langford convoy of three SUVs for their intended targets.

Langford said one of the kidnapped victims’ relatives received a phone call from the missing women. She heard a woman screaming and men talking loudly, said Langford, who has been speaking with the families in Mexico.

This is Christina Langford Johnson & her baby Faith and the other pic is Dawna Ray Langford, her husband David, 12 of 13...

Posted by Amber Bostwick on Monday, November 4, 2019

Mexico’s federal Department of Security and Citizens’ Protection said security forces were reinforced with National Guard, army and state police troops in the area after “the reports about disappearance and aggression against several people.” They also were helping to search for missing family members believed to have fled when they came under attack.

The victims are part of a community in Mexico where the residents often have both U.S. and Mexican citizenship and have intermarried among Mormon churches.

It was the first time that members of the breakaway church had been attacked in northern Mexico, where their forebears settled — often in Chihuahua state — decades ago.

In 2009, Benjamin LeBaron, an anti-crime activist who was related to those killed in Monday’s attack, was murdered in 2009 in neighboring Chihuahua state.

The New York Times and The Associated Press contributed to this report.