COLONIA LEBARON, Mexico (Reuters) - Hundreds of mourners gathered on Friday for the burial of a mother, her months-old twins and two other children on the fringes of a township founded by breakaway Mormons in Mexico, in a second funeral for the victims of a brazen armed ambush.

Suspected cartel gunmen attacked Rhonita Miller LeBaron, 30, and four of her children on Monday, also striking two other vehicles, killing a total of three women and six children on an isolated dirt road in the hills of Sonora. All of the victims were dual U.S.-Mexican citizens.

Miller’s SUV exploded in flames during the attack, incinerating her along with her 13-year-old son, 11-year old daughter and 7-month-old twins, Titus and Tiana.

“We pray, Father, that good will come out of this terrible incident, that the way may be opened up for this country to find justice for those that don’t have a voice,” said Rhonita’s father-in-law, Kenny Miller, speaking at the graveside where children lay flowers as a soft rain fell.

On Thursday in La Mora, the first funeral was held for victims of the attack, with mourners guarded by heavily armed soldiers.

More than 250,000 Mexicans have been killed in the mounting violence that has gripped the country since 2007, many of them victims of drug-related crimes. Tens of thousands more are missing.

Echoing sentiments expressed by relatives in recent days, Miller said the cartels had grown stronger than the government in some areas, comparing the situation to conflicts in the Middle East. He stopped short, however, of supporting emerging calls for the United States to take a larger role in Mexico.

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“I witnessed the army, scared to go in,” Miller said, apparently describing the day of the attack, which occurred in the morning, when cartel firefighting lasted for hours, restricting search parties. Authorities did not arrive until sundown.

“That is uncalled for in a sovereign country,” Miller said at the cemetery outside the town of Colonia LeBaron. Nearby a rusting road sign was punctured with bulletholes.

“WORSE THAN ISIS”

His voice trembling, Miller described the horror of finding the young family’s vehicle in roaring flames, not knowing if they were inside, and returning hours later to find their charred remains. He called it an act of terrorism.

Both the families and the governments blame warring drug cartels, although they disagree whether the families were targeted or victims of mistaken identity in the attack.

“They talk about terrorism in Iraq and Iran, those aren’t our countries, this is our country. We’ve got terrorists here,” Miller said.

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The victims were all part of a community of breakaway Mormon sects who arrived in Mexico from the 1880s onwards to escape a clampdown on polygamy in the United States.

A shrinking number still practice polygamy, but families are large. Rhonita Miller is survived by her husband and three other children. The mourners arrived in a convoy of dozens of trucks in Colonia LeBaron on Friday after a five-hour drive across backroads from La Mora, where the victims all lived.

The ambush took place on a track near La Mora.

“I really believe that the cartels in Mexico have moved to another level of barbarity, they are as bad or worse than ISIS. ISIS have an ideology,” said resident Rosa LeBaron, 65, whose cousins, nieces and nephews died in the attacks. “These sicarios, why are they doing it?” she said, using a term for “hitmen.” “Out of greed and pure evil.”

She said Mexico needed to overcome pride and accept outside help from a neighboring country or international coalition, like the United Nations, to stamp out the cartels.

“This is so beyond comprehension, we’re living like we’re in Afghanistan, 100 miles from the U.S. border,” LeBaron said. “They have to wipe these bad men out of Mexico just like the coalition that goes into Syria and these places.”

President Andres Manuel Lopez Obrador said he believed Mexico could resolve its security problems without foreign “intervention,” but he has opened the door to FBI cooperation provided the country’s national sovereignty is not violated.

U.S. Senator Josh Hawley, a Republican, said this week that the United States should impose sanctions on Mexican officials “who won’t confront cartels.”

The killings follow a series of mass shootings that have piled pressure on Lopez Obrador to make good on his 2018 election campaign pledge to end violence.

However, he has resisted taking a tougher line with the gangs, instead pursuing a strategy of non-confrontation he calls “hugs not bullets” and arguing he can end violence by addressing the root causes of crime such as poverty and joblessness.

Adrian LeBaron, whose daughter and grandchildren died in the attack, reflected the views of several other relatives who said they had little faith in Mexico’s judicial system and federal government, but still hopes the country will rise to the challenge.

“I love Mexico, and this happened in Mexico, and these children are Mexican,” he said. “The FBI, the whole world, must be dying to do something, but it wouldn’t be right... we should be able to do it.”