Authorities said at least 14 people were killed in the Mexican border city of Reynosa on Saturday after a convoy of shooters went on a rampage, a somber reminder of the violence that has ravaged the United States’ neighbor for more than a decade.

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, according to a spokesman for Tamaulipas state’s secretary of public security on Sunday.

According to Luis Alberto Rodrguez, the spokesman, the attacks may have resulted from a dispute between rival groups over territorial control of the area and dominance over illicit operations such as drug trafficking and human trafficking. He also claimed that four suspects were killed.

The attacks began early in the afternoon, according to the State Coordinating Group for Peace Building in Tamaulipas, an agency that coordinates security forces and law enforcement, when shooters in vehicles attacked several neighborhoods in Reynosa, about 10 miles south of McAllen, Texas. According to a statement from the agency, the Mexican army and state police fanned out across the city in a joint operation to find the attackers.

According to the statement, state police discovered suspects who resisted arrest and shot at them before officers opened fire, killing two men and one woman.

State authorities said on Sunday that they are looking into possible motives for the killings and are on the lookout for additional shooters.

Another suspect was killed during a shootout with state police. According to the agency that coordinates security forces, after that confrontation, police arrested one man and discovered two women in the trunk of his vehicle who are believed to have been kidnapped. At the scene, three sport-utility vehicles and one long gun were discovered.

Cabeza de Vaca also chastised the federal government, urging it to “assume its responsibility” in combating “those who threaten the security, health, and stability” of Mexican communities, implying that the pervasive violence in the border state is exacerbated in part by President Andrés Manuel López Obrador’s lack of action.

López Obrador, also known by his initials AMLO, has stated that he will not repeat the mistakes of previous administrations that failed to contain cartel violence, which increased after President Felipe Calderón launched a military crackdown on the gangs in 2006. López Obrador has prioritized social programs to address the underlying causes of crime.

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

According to Guerrero, the Cartel del Golfo — the Gulf drug cartel — has virtually vanished after splintering into groups across the state that are involved in a variety of criminal activities ranging from oil theft to arms trafficking, drug trafficking, and human trafficking. Drug-related violence in Tamaulipas has decreased in recent years as a result of better-trained and better-coordinated police, according to Guerrero, but these efforts have not stopped the flow of blood in Reynosa.

The attacks on Saturday come amid a slew of scandals that threaten to depose the governor. According to the Mexican attorney general’s office, Cabeza de Vaca is being investigated for alleged links to organized crime groups, money laundering, and tax evasion. The US Justice Department shared a case file on Cabeza de Vaca in May. During a news conference in May, López Obrador stated that the FBI is looking into him for alleged money laundering.

Mexico has been plagued by extreme violence linked to organized crime for more than a decade, as drug cartels compete for strategic routes to the United States. They have recently expanded into a variety of other illegal activities. The Gulf, Northeast, and Jalisco cartels are vying for control of Tamaulipas’ lucrative drug and arms trafficking routes to and from the US.