MEXICO CITY – One of the Gulf drug cartel’s top bosses has been arrested, dealing a blow to the powerful Mexican criminal organization less than three months before President Felipe Calderon leaves office, officials said.

Mario Cardenas Guillen, known as “El Gordo” (The Fat Guy) and “M1,” was captured Monday by marines in the northeastern state of Tamaulipas, one of the areas most affected by drug-related violence in recent years.

He is the brother of former Gulf cartel top capos Osiel Cardenas Guillen, who was extradited to the United States on Jan. 20, 2007, and Antonio Ezequiel Cardenas Guillen, who died in a shootout with marines nearly two years ago.

The Gulf cartel, one of Mexico’s oldest drug trafficking organizations, was founded by Juan Nepomuceno Guerra in the 1970s and was later led by Juan Garcia Abrego, who was arrested in 1996 and extradited to the United States.

Osiel Cardenas Guillen took over the cartel’s leadership in July 1999, but he was arrested in 2003. He continued running the Gulf cartel, one of the most violent criminal organizations in Mexico, until his extradition to the United States four years later.

He was succeeded by his brother, Antonio Ezequiel, known as “Tony Tormenta,” and Jorge Eduardo Costilla Sanchez, known as “El Coss.”

Antonio Ezequiel Cardenas Guillen was killed in a shootout with marines on Nov. 5, 2010, and it was believed that Costilla Sanchez had been running the cartel since his death.

Mario Cardenas Guillen was in charge of one of the two branches of the cartel, while Costilla Sanchez, who is still at large, ran the other, a navy spokesman said.

The nearly 70-year-old Cardenas Guillen was paraded before reporters on Tuesday wearing a bullet-proof vest, appearing somber and with a bruise on his face.

He was identified as “someone who says” he is Mario Cardenas Guillen, which is standard procedure until a full identification is made.

The cartel boss was arrested in 1995 on a variety of drug-related charges, but he was released from prison in 2007, navy spokesman Rear Adm. Jose Luis Vergara said.

Cardenas Guillen oversaw the smuggling of large shipments of cocaine and marijuana from his prison cell in Matamoros, a border city in Tamaulipas, prompting his transfer to the Puente Grande prison in the western state of Jalisco, where he stayed until his release, Vergara said.

Marines seized a rifle, three ammunition clips, two grenades, 129,700 pesos ($9,800) in cash, communications gear, a vehicle and some cocaine from the suspect.

The Gulf cartel is no longer as powerful as it was in the past, partly because of its break with Los Zetas, the criminal organization’s former armed wing, which severed ties with the cartel in 2010 and now runs its own narcotics trafficking business.

The Gulf organization, which mainly deals in cocaine, synthetic drugs and marijuana, mostly operates in northern Mexico and the country’s eastern coastal areas.

The cartel, like other Mexican criminal organizations, has expanded into kidnappings and extortion rackets, targeting businesses.

Mario Cardenas Guillen’s arrest comes as Mexico is entering the political transition that will end with the inauguration on Dec. 1 of Enrique Peña Nieto, who won the July 1 presidential election.

The cartel leader’s arrest was announced on Tuesday, the same day that Peña Nieto, of the Institutional Revolutionary Party, or PRI, named his transition team, which will oversee the handover of power from Calderon, of the conservative National Action Party, or PAN.

Calderon made fighting Mexico’s drug cartels the focus of his internal security policy after taking office on Dec. 1, 2006.

The president has deployed tens of thousands of soldiers and Federal Police officers across the country to combat drug cartels and other criminal organizations.

The use of the armed forces to fight drug traffickers, however, has failed to stem the violence.

Mexico registered 27,199 murders in 2011, or 24 per 100,000 people, the highest number since Calderon took office, the National Institute of Statistics and Geography, or INEGI, said in a report released last month.

The Movement for Peace with Justice and Dignity, which was founded by human rights activist and poet Javier Sicilia, puts the death toll from Mexico’s drug war at 70,000.

A military commander based in northern Mexico told Efe that Mario Cardenas Guillen’s arrest could lead to more violence in the region, which borders the United States.

“With the arrest of Cardenas Guillen, the situation will get difficult, there could be more violence,” the military officer told Efe on condition of anonymity.

The cartel boss’s arrest could lead to a “readjustment of the command” structure and the effort to dominate northern Mexico “will make the criminal organizations increase their clashes with greater violence,” the military commander said. EFE