At least 14 people died in the Mexican border city of Reynosa on Saturday after a convoy of shooters went on a rampage, authorities said, a somber reminder of the violence that has ravaged the U.S. neighbor for more than a decade.

A spokesman for Tamaulipas state’s secretary of public security said Sunday that the attackers may be members of a splinter faction of the Gulf Cartel, which has a presence in large swaths of the Mexican state that borders Texas.

The attacks may have derived from a dispute between rival groups over territorial control of the area and dominance over illicit operations including drug trafficking and human trafficking, Luis Alberto Rodríguez, the spokesman, told The Washington Post on Sunday. Four suspects also died, he said.

The State Coordinating Group for Peace Building in Tamaulipas, an agency coordinating security forces and law enforcement, said the attacks began early in the afternoon, when shooters in vehicles attacked several neighborhoods in Reynosa, about 10 miles south of McAllen, Tex.

In a joint operation, the Mexican army and state police fanned out across the city to find the attackers, according to a statement from the agency.

State police found suspects who resisted arrest and shot at them, the statement said, before officers fired back and killed two men and one woman.

State authorities said Sunday that they are investigating possible motives behind the killings and looking for other shooters.

During a shootout with state police, another suspect was killed. After that confrontation, police arrested one man and found two women in the trunk of his vehicle who are believed to have been kidnapped, said the agency that coordinates security forces. Three sport-utility vehicles and one long gun were found at the scene.

The coordinating agency released no details about the 14 people killed by attackers, but local media reports said one family could have been killed.

Tamaulipas Gov. Francisco García Cabeza de Vaca said in a statement Sunday that he has ordered a “speedy” investigation.

“I express my solidarity to the families of the innocent victims that died as consequences of these actions of organized crime in Reynosa,” the statement said.

Cabeza de Vaca also criticized the federal government, urging it to “assume its responsibility” in combating “those who threaten the security, health and stability” of Mexican communities, suggesting the pervasive violence in the border state is caused in part by a lack of action from President Andrés Manuel López Obrador.

“Criminal organizations should receive a clear, explicit and stern signal from the federal government that there will be no space for impunity, nor tolerance facing criminal conduct,” the governor’s statement added.

Eduardo Guerrero, a security analyst based in Mexico City, said the governor’s swipe was a response to what critics have called a lenient stance on drug crime.

“The president arrived in power with a rhetoric of nonconfrontation with a ‘Hugs, not gunshots’ slogan that has led to federal forces having a passive presence in certain areas of the country, which has empowered criminal organizations to act more freely,” Guerrero said.

López Obrador, often referred to by his initials, AMLO, has said he would not repeat the mistakes of previous administrations that did not contain cartel violence, which surged after President Felipe Calderón launched a military crackdown on the gangs in 2006. López Obrador has focused on social programs to deal with the roots of crime.

He has also deployed armed forces, as his predecessors did, and created a national guard to respond to the violence.

Guerrero has identified more than 210 cartels, gangs and regional bands operating across the country, of which 13 are in Tamaulipas. One is Cartel Jalisco Nueva Generación — the New Generation Jalisco cartel — one of the most powerful drug organizations in Mexico.

The Cartel del Golfo — the Gulf drug cartel — has virtually disappeared after splintering into groups across the state that are involved in a wide range of criminal activities, from oil theft to arms trafficking, drug trafficking and human trafficking, Guerrero said.

Drug-related violence in Tamaulipas has decreased in the past few years because of better-trained and better-coordinated police, Guerrero added, but these efforts have not stopped blood from flowing in Reynosa.

Saturday’s attacks come amid scandals that threaten to oust the governor. Cabeza de Vaca is under an investigation for alleged links to organized crime groups, money laundering and tax evasion, according to the Mexican attorney general’s office, which announced in May that the U.S. Justice Department has shared a case file on Cabeza de Vaca. López Obrador said during a May news conference that the FBI is investigating the governor for alleged money laundering.

Cabeza de Vaca has denied the accusations, which he called baseless and politically motivated.

The governor was scrutinized after authorities arrested several members of an elite special operations group during an investigation into the January massacre of 19 people, including 13 Guatemalan migrants, near the U.S.-Mexico border.

For more than a decade, Mexico has experienced extreme violence linked to organized crime as drug cartels fight over strategic routes to the United States. Recently, they have diversified into an array of other illegal activities. The Gulf, Northeast and Jalisco cartels are fighting for control over Tamaulipas’s lucrative drug and arms trafficking routes to and from the United States.

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