A gun battle between rival Mexican drug cartels has once again left eight people dead near the U.S.-Mexico border.

Residents of Tamaulipas on Monday said that the gun battles, which also left a string of burned-out armored trucks on a roadway, happened on Saturday and went on until Sunday in Santa Rosalia, located at the border of Camargo in Mexico.

The residents were not named as they fear retaliation, according to Associated Press. They said the charred bodies were found lying in or near the burned-out trucks, with at least three of which had welded steel plates that served as improvised armor.

The residents added that law enforcers only managed to get into the area during the daytime over the weekend. However, the gunmen of the Mexican drug cartels reappeared at night to continue their battle.

According to Mexican President Andres Manuel Lopez Obrador, the gun battle was between two rival Mexican drug cartels. The president added that many people had been killed in the gun battle.

The area has long been caught in the middle of a turf war between the Northeast cartel, an old Zetas gang remnant, and the Gulf cartel, according to an Associated Press report.

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Mexican Drug Cartels

Mexican drug cartels engaged in a deadly turf war have claimed thousands of lives every year as they continue to fight over territory and influence.

The Sinaloa Cartel is considered one of Mexico's most influential drug cartels, with much of the northwest areas as their territory.

The group was founded in the late 1980s and headed by the notorious drug kingpin Joaquín "El Chapo" Guzmán. According to BBC, "El Chapo" or "Short" was once ranked as one of the world's richest men.

Under El Chapo's leadership, the Sinaloa Cartel earned its reputation through violence and outfought several rival groups. Officials said that the Sinaloa Cartel became the biggest supplier of illegal drugs to the U.S. during El Chapo's reign.

The Jalisco New Generation Cartel is considered to be one of the most aggressive and strongest competitors of the Sinaloa cartel.

The Jalisco cartel has set its foothold in the west, mainly the Tierra Caliente region. The group was formed in 2010 and has rapidly expanded its reach across Mexico.

One of the oldest criminal groups in Mexico was the Gulf Cartel. Its history could be traced back to the 1980s. 

The group is known for trafficking cocaine and marijuana into the U.S. The Gulf Cartel was also reported to have worked closely with other drug cartels in Colombia.

On the other hand, the Los Zetas Cartel was founded by corrupt members of an elite unit of Mexico's special forces. In the 1990s, the leader of the Gulf Cartel hired more than 30 former soldiers, but they broke away from the cartel and formed their own operation in 2010.

Mexican Drug War

Efforts to address the issue of drugs in the country can be traced back to the presidency of Felipe Calderon.

Calderon declared war on drugs against drug cartels shortly after taking office. He then deployed tens of thousands of military personnel to aid and replace local police officers who were viewed as corrupt, according to a Council On Foreign Relations report.

The Mexican authorities managed to capture and kill 25 of the top 37 drug kingpins in Mexico. The militarized crackdown was among the legacies of Calderon's presidency.

Former Mexican President Enrique Pena Nieto focused more on reducing violence against civilians and businesses during his tenure. Calderon's successor relied on the military to fight cartels with the help of the federal police.

For his part, Lopez Obrador announced that his government would move away from attempts to capture leaders of the Mexican drug cartels.

The current Mexican president said that he would focus more on improving security and improving the homicide rates.

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