Sen. Mitt Romney (R-UT) on Tuesday expressed his condolences in the wake of a Mexican cartel attack that left at least nine American Mormons dead in the border state of Sonora and called for the U.S. and Mexico to hold the suspects “accountable.”

“Ann and I are heartbroken for the victims of the horrific attacks in Mexico. Our prayers are with their families who have suffered such an unspeakable tragedy,” Romney, a prominent member of The Church of Jesus Christ of Latter-day Saints, wrote on social media. “The U.S. must work with Mexican officials to hold accountable those responsible for this senseless violence.”

Ann and I are heartbroken for the victims of the horrific attacks in Mexico. 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. — Mitt Romney (@MittRomney) November 5, 2019

At least nine American relatives, including several children, were killed after their vehicles were ambushed on a Mexican highway as they traveled to a wedding, authorities said.

The families were driving from Bavispe to LaBaron, Mexico when they were ambushed by gunfire. One of the vehicles exploded in flames and some of the family members were kidnapped. The travelers, who live in Queen Creek, Arizona belong to a Mormon ranching community that’s been in Bavispe for more than 40 years.

Twin four-month-old babies were among the dead. At least three other children were wounded.

President Donald Trump reacted angrily to the attack and vowed to help assist Mexico with its ongoing issues with drug cartels.

….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! — Donald J. Trump (@realDonaldTrump) November 5, 2019

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! — Donald J. Trump (@realDonaldTrump) November 5, 2019

“If Mexico needs or requests help cleaning out these monsters, the United States stands ready, willing & able to get involved and do the job quickly and effectively,” he tweeted.

“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.”

Sonora Gov. Claudia Paviovich Arellano said she felt “deep pain” for the victims and vowed to punish the “cowards” who attacked the family.

Como madre siento coraje, repudio y un profundo dolor por los cobardes hechos en la sierra entre Sonora y Chihuahua. No sé qué clase de monstruos se atreven a lastimar a mujeres y niños. Como Gobernadora toda mi colaboración para que no quede impune y paguen los responsables. — Claudia Pavlovich A. (@ClaudiaPavlovic) November 5, 2019

“As a mother I feel courage, repudiation and deep pain for what cowards did in the mountains between Sonora and Chihuahua,” she tweeted. “I don’t know what kind of monsters dare to hurt women and children. As governor, I will do everything to make sure this does not go unpunished and those responsible pay.”

The UPI contributed to this report.