(Photo: AP)

Mexico’s foreign secretary says President Andrés Manuel López Obrador has phoned US President Donald Trump to express condolences at the slaying of nine members of a religious community in northern Mexico, saying they were citizens of both nations.

Marcelo Ebrard says the Mexican leader expressed “thanks for the offer of help, if Mexico needs some sort of help.” And he said Trump “reiterated confidence” in Mexican authorities “to apply justice.”

The comments were carried in a video on the Reporte Indigo news website.

Earlier Tuesday, Trump tweeted an offer to help Mexico “wage WAR” against drug cartels suspected of committing the killing in a mountainous part of northern Mexico.

López Obrador expressed thanks to Trump during a later news conference, but demurred at Trump’s offer, saying “The worst thing you can have is war.”

Sen. Mitt Romney says he’s been briefed on the slaying of nine US citizens in northern Mexico and calls it “a great tragedy” and something “really unthinkable.”

The Republican from Utah said Tuesday that the attacks were probably “associated with the business of the cartels” rather than a targeted attack on the US-affiliated religious community.

He said he agrees with President Trump that “Mexico has to really knuckle down and go after some of these cartels and stop this escalating level of violence.”

The victims are members of a faction that long ago broke away from The Church of Jesus Christ of Latter-day Saints and some have family ties in Utah.

Romney’s own father was born in a similar but different group in northern Mexico. He said he doesn’t know any of the people involved.

A Utah man says the three women killed by drug cartel gunmen in northern Mexico were his aunt and two cousins and that they were all traveling with children in three vehicles on a dirt road that they had used frequently without problems.

Taylor Langford said in an interview Tuesday that he was provided with an account of what happened by his father and his uncle, who Langford says went to the scene of the slaughter where six children were also killed and spoke with Mexican authorities.

Langford says a car driven by Rhonita Miller that was about 10 miles (16 kilometers) behind the other two cars was shot first until it engulfed in flames, burning her and her four children, including twin babies.

He says the other two cars were attacked next and that Christina Langford had her baby in her car and Dawna Langford had nine children in hers.

Langford says a 9-year-old girl shot in the arm and found hours later was among the children who survived.

He says Miller was on her way to Phoenix to pick up her husband from the airport and that the other two women were on their way to visit relatives who live in Mexico.

“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!” Trump said in a series of tweets addressing the tragedy.

Trump added that the US government stands ready to get involved. He said that Andrés Manuel López Obrador has made fighting drug cartels a top issue.

“But the cartels have become so large and powerful that you sometimes need an army to defeat an army! ”

López Obrador has favored a less militaristic approach to the problem, saying a policy of frontal confrontations by his predecessors led only to more violence