Border agents on high alert following capture of top cartel leader 'El Bola' in northern Mexico

Texas Border Patrol agents have been placed on high alert following the capture of a high-ranking cartel leader in northern Mexico, an event that has led to attacks in the area.

Carlos Munsivais Treviño, a leader of the Cartel del Noreste and known as "El Bola," was arrested on September 3 in Nuevo Laredo, Tamaulipas. He was taken by Mexican forces and taken to the capital to face charges.

A memo from the Laredo Sector Intelligence Unit warns that this could lead to increased "cross-border violence in the form of retaliatory attacks," according to a memo seen by NewsNation.

The document advises agents be more cautious when dealing with "military-aged undocumented noncitizens along the border," as cartel combatants could be seeking to enter the U.S. following the capture of the cartel's second most important agent.

According to local media, he was in charge of organizing kidnappings, extortion and drug and migrant trafficking, as well as attacks against the Mexican military. The cartel is based in Nuevo Laredo, close to the Texas border, but also operates throughout Mexico, the U.S., Honduras, Guatemala and Colombia.

His capture comes as Mexican cartels are embroiled in turmoil following the arrest in the U.S. of Ismael "El Mayo" Zambada and Joaquín Guzmán López in late July. The Mexican army was attacked last week in Sinaloa after the arrests, with media reporting images of burning cars blocking roads, images that have already been seen in the region during clashes with cartels.

Even though there didn't seem to be a clear reason for the attack, Zambada's arrest has further destabilized an already volatile region. While the Mexican government has delivered stern warnings (and pleas) to organized crime in the region, hoping to prevent a full-out war between warring factions in the Sinaloa Cartel, things are heating up, as many analysts expected, especially as Zambada has accused Guzmán of ambushing and delivering him to U.S. authorities.

The government has sent at least 1,000 troops to the region in an attempt to help prevent an explosion of violence. But despite the military presence, cartel members from both sides have begun mobilizing, with reports of gunmen being recruited and weapons stockpiled. A source close to Zambada's operations indicated that the "Chapitos," as Guzmán López and his brothers are known, have as many as 5,000 gunmen at their disposal, while Zambada's faction, known as the Mayiza, relies on alliances forged over decades.

At the same time, the Biden administration is set to hand over Osiel Cardenas, a notorious drug cartel leader, to Mexico after releasing him from prison last week.

Cardenas, who led the Gulf Cartel and founded the Zetas, an armed organization that played a salient role in violent turf wars that marked Mexico, was imprisoned in the U.S. for 14 years.

He was released last week from a prison in Indiana and went on to be guarded by Immigration and Customs Enforcement (ICE) before his expected extradition, a government official told NBC News. He is now set to face pending charges in his home country.

Another development involved Mexican prosecutors saying that Joaquín Guzmán López, a son of "El Chapo" Guzmán, turned himself in and managed to hand over "El Mayo" Zambada to American authorities in exchange for getting his brother Ovidio transferred out of prison.