MEXICO CITY — Assailants have killed at least seven members of a Mormon family in northern Mexico, national media reported Tuesday, burning alive a woman and her children in a brutal assault that highlighted the growing danger posed by organized-crime groups around the country.

The daily Reforma reported that the victims included three women and four children. Another publication, El Universal, cited relatives saying that a dozen family members were killed — three women and nine children. They were part of a community of dual U.S.-Mexican citizens.

Mexican authorities said they have not yet confirmed the number of the victims.

Relatives posted video of a charred vehicle in which the victims had been traveling.

"This is how we live under the government of @lopezobrador," tweeted Alex LeBaron, referring to President Andrés Manuel López Obrador. "Mexican Mormons, innocent women and children were ambushed in the Chihuahua sierra, shot and burned alive by the Cartels that rule in Mexico!"

The attack occurred on Monday when two of the women were driving a group of children from Bavispe, in Sonora state, to a Mormon community known as La Mora in neighboring Chihuahua state. Organized-crime groups in the area have been fighting and may have initially mistaken the vehicles for their rivals, according to news reports.

One vehicle, driven by Rhonita Miller LeBaron, had a flat tire, and the second car turned back to get help, according to the reports. The assailants attacked the first car, killing the driver and her four children — including two 6-month-old twins, according to the reports. They then set the vehicle on fire.

When the rest of the group returned to the site in two vehicles, they were also ambushed. Several other children escaped.

The attack occurred as Mexico is in an uproar over a botched anti-drug raid last month. In that incident, Sinaloa Cartel gunmen seized control of the city after soldiers attempted to arrest Ovidio Guzmán, son of notorious drug trafficker Joaquin "El Chapo" Guzmán, on a U.S. extradition warrant. The government relinquished the younger Guzmán rather than risk what it feared would be a bloodbath.

"Hard to imagine that what happened in #Sonora today won't impact [Mexico-U.S.] relations and security policy in [Mexico]," wrote Falko Ernst, Mexico analyst for the International Crisis Group, on Twitter. "Over the next days, I'd expect pressure within the U.S. to build on the Trump [administration] — by media and evangelicals, e.g. — and for that pressure to be passed onto Lopez Obrador."

The LeBarons are descendants of Mormons who moved to Mexico in 1924, after disagreeing with the central church over polygamy. For decades, they lived quietly in farming communities, maintaining close ties with the United States and speaking both Spanish and English.

But their relative wealth made them targets of extortion and kidnapping when organized-crime groups began to assert themselves in northern Mexico. In 2009, a prominent member of the clan, Benjamin LeBaron, 31, was shot dead near his community in northern Mexico. He had publicly denounced the drug traffickers, who had earlier abducted his younger brother, demanding a $1 million ransom. (The family refused to pay). The killers left a message saying they were retaliating for LeBaron's activism.

The latest attack coincided with a visit to Sonora by U.S. Ambassador Christopher Landau. "The security of our fellow [U.S.] citizens is our priority," he tweeted. "I am following closely the situation in the mountains between Sonora and Chihuahua."