WASHINGTON, Nov. 5 (Xinhua) -- U.S. President Donald Trump spoke on phone Tuesday with his Mexican counterpart, Andres Manuel Lopez Obrador, about the recent deadly attack in Mexico that killed nine U.S. citizens.

The two leaders discussed the recent violence in Mexico and efforts to combat the growing violent behavior of criminal groups in the region, the White House said in a statement.

"Trump made clear that the United States condemns these senseless acts of violence that took the lives of nine American citizens and offered Mexico assistance to ensure the perpetrators face justice," the statement added.

At least nine members of an American family, including three mothers and six children, were ambushed and killed by suspected members of a drug cartel in northern Mexico Monday afternoon, Mexican officials said on Tuesday.

The victims -- all members of a Mormon family that live in northern Chihuahua state but have U.S. nationality -- were traveling in at least two vehicles along a dirt road between Chihuahua and neighboring Sonora state when they came under attack.

"The convoy ... could have been mistaken by criminal groups fighting for control of the region," Lopez Obrador said Tuesday at his daily press conference.

Trump tweeted earlier that "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."

Lopez Obrador said he appreciated the offer but would not accept it. "This is a matter for us, the government of Mexico, to deal with independently," he added.