MEXICO CITY, Sept 13 (Reuters) - The Mexican Navy said on Wednesday it had captured one of Mexico's most wanted drug bosses, the head of the Gulf Cartel, in what would mark a major victory in President Felipe Calderon's crackdown on organized crime.

The Navy said it would give more details about the arrest of the man it believed to be Jorge Costilla, alias "El Coss," when it parades him in front of the media early on Thursday.

A government security official said Costilla, 41, was detained in Tampico in northeastern Mexico, where the cartel is active, without putting up a fight. The U.S. State Department has a reward of up to $5 million for his capture.

No other details were immediately available.

The arrest of the suspected capo comes barely a week after the Mexican Navy captured senior Gulf Cartel member Mario Cardenas, alias "Fatso," also in the state of Tamaulipas where Costilla was caught.

The Gulf Cartel has been weakened by a violent turf war with the Zetas, a gang formed by army deserters which acted as enforcers for the cartel before breaking with their employers in 2010.

It could also have political implications because top officials in the cartel's stronghold of Tamaulipas have been accused of taking money from local drug gangs.

"All these politicians who were getting money from the Gulf Cartel ought to be very worried now because this information is going to come to light in Mexico or the United States," said Alberto Islas, a security expert at consultancy Risk Evaluation, after hearing the reports of Costilla's capture.

Costilla features prominently on a wanted list of 37 kingpins the Mexican government published in 2009. Well over 20 on that list have now been captured or killed.

Still, the Mexican Navy has erred before in its claims, saying in June it had captured a son of Mexico's most wanted man Joaquin "Shorty" Guzman, only to later admit that it had not.


DAMAGING REVELATIONS

Islas said he expected Costilla to be extradited to the United States, and that his testimony could prove damaging to officials in Tamaulipas and neighboring Veracruz state, which has also been dogged by allegations of corruption.

Tomas Yarrington, a governor of Tamaulipas between 1999 and 2005, is fugitive and wanted in Mexico for aiding drug gangs.

Yarrington governed Tamaulipas for the Institutional Revolutionary Party (PRI), which will retake the presidency in December after its candidate Enrique Pena Nieto won a July 1 election. The PRI suspended Yarrington from the party in May.

Islas said damaging revelations about graft would raise pressure on Pena Nieto to take steps to clean up the image of the centrist PRI, which governed Mexico between 1929 and 2000. That rule was tainted by frequent allegations of corruption.

The FBI said Costilla is believed to have taken over the daily operations of the cartel after his former boss Osiel Cardenas was arrested and jailed in Mexico in 2003.

It said a federal arrest warrant was issued for Costilla in Texas in 2002, and that he was charged with drug offenses, threatening to assault and murder federal agents, and money laundering.

The FBI's wanted notice includes a grainy photograph of Costilla wearing a cowboy hat and a moustache.

With Costilla's apparent capture, the cartel is looking increasingly weak, and bloody turf wars for control of the northeastern border with Texas would now intensify. "There will be an increase in violence there," Islas said.

The stage was now set for increased hostilities in the region between Mexico's two most powerful gangs, Guzman's Sinaloa Cartel and the Zetas, he noted.

This could prove a headache for Pena Nieto, who has vowed to quickly reduce the number of beheadings and mass executions. There have been more than 55,000 drug-related deaths in Calderon's six-year offensive against cartels.

Earlier on HuffPost:

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  • May 13, 2012

    Suspected drug gang hitmen dumped 49 mutilated bodies, stuffed in bags, on a highway outside the northern industrial city of Monterrey. <em>Caption: Federal police stand guard on a vehicle behind a forensic truck containing bodies found on the highway connecting the northern Mexican metropolis of Monterrey to the U.S. border, along the Reynosa-Cadereyta road, in the town of San Juan near the city of Monterrey, Mexico, Sunday, May 13, 2012. (AP Photo/Christian Palma)</em>

  • May 4, 2012

    The bodies of nine people were found hanging from a bridge and 14 others found dismembered in the city of Nuevo Laredo, just across the U.S. border from Laredo, in Texas. <em>Caption: Four of nine corpses are seen hanging from a bridge in the Mexican border city of Nuevo Laredo, Tamaulipas state, early morning on May 4, 2012. (RAUL LLAMAS/AFP/GettyImages)</em>

  • Feb 19, 2012

    A fight between rival gangs at a prison just outside Monterrey in northern Mexico leaves 44 dead. <em>Caption: Araceli Guevara Ontiveros, the sister of Francisco Guevara Ontiveros --one of the 44 dead in a riot at The Apodaca prison-- is comforted while crying on his coffin during his wake in Monterrey, Nuevo Leon state, on February 21, 2012. (Julio Cesar Aguilar/AFP/Getty Images)</em>

  • Nov 24, 2011

    More than 20 bodies are found in cars in Mexico's second city, Guadalajara, a day after the burned bodies of 16 people are found in the home state of the country's powerful drug lord, Joaquin "Shorty" Guzman. <em>Caption: A member of the forensic service carries one of the 26 corpses found this morning in three vehicles abandoned in Mexico's second most populous city of Guadalajara, Mexico, on November 24, 2011. (HECTOR GUERRERO/AFP/Getty Images)</em>

  • Oct 6, 2011

    Mexican security forces find 32 bodies at several locations around Veracruz, just two days after the government unveiled a plan to bolster security in Veracruz state. <em>Caption: Mexican army soldiers walk towards their vehicle after seven bodies were found inside a vehicle in the Gulf port city of Veracruz, Mexico, late Friday Oct. 7, 2011. (AP Photo/Felix Marquez)</em>

  • Sept 20, 2011

    Thirty-five bodies are found abandoned in two trucks on an underpass in the eastern Gulf city of Veracruz, which had been largely untouched by the violence. <em>Caption: Mexican marines stand guard in streets of Veracruz State, Mexico on 24 January 2012. (JOHAN ORDONEZ/AFP/Getty Images)</em>

  • Aug 25, 2011

    Masked gunmen torch a casino in Monterrey, killing 52 people, most of them women. The attack takes less than three minutes. <em>Caption: Relatives of victims cry in front of the Casino Royale, in Monterrey, Mexico, on August 27, 2011. (Ronaldo Schemidt/AFP/Getty Images)</em>

  • Aug 20, 2011

    Five headless bodies were found in Acapulco, taking the number of people killed in the popular Pacific resort to at least 25 in that one week. <em>Caption: Forensic personnel move the corpse of a person murdered in a hotel at the La Guinea neighbordhood in the town of Acapulco, Guerrero state, Mexico on August 24, 2011. (Pedro PARDO/AFP/Getty Images)</em>

  • April 2011

    Officials unearthed the first of what turned out to be more than 450 bodies buried in mass graves in the northern states of Durango and Tamaulipas. <em>Caption: Forensic personnel unload at the morgue bodies of people killed execution-style in Matamoros, Tamaulipas State, Mexico, on April, 11, 2011. (STR/AFP/Getty Images)</em>

  • Aug 25, 2010

    Marines found the bodies of 58 men and 14 women at a ranch near the Gulf of Mexico in Tamaulipas state, 90 miles from the Texas border, after a firefight with drug hitmen in which three gunmen and a marine died. <em>Caption: A worker wearing protective suit and boots walks between two refrigerated trucks parked outside a funeral home where the bodies of 72 men and women that were allegedly killed by the Zetas drug gang, are kept in San Fernando, just 100 miles from the the Mexican border with the U.S. near the city of Matamoros, Thursday Aug. 26, 2010. (AP Photo/Guillermo Arias)</em>

  • July 24, 2010

    Police unearthed 51 bodies in a grave outside Mexico's business capital, Monterrey, in northern Mexico over several days. Some corpses were burned beyond recognition. <em>Caption: View of the remains of two burnt bodies found in Monterrey, Nuevo Leon state, on October 20, 2010. The bodies were found under burnt wooden pallets. (Dario Leon/AFP/Getty Images)</em>

  • July 18, 2010

    Gunmen burst into a birthday party in the northern city of Torreon, using automatic weapons to kill 17 party-goers and wound 18 others. Mexican authorities said later those responsible were incarcerated cartel hitmen let out of jail by corrupt officials. The killers allegedly borrowed weapons and vehicles from prison guards and later returned to their cells. <em>Caption: Police officers patrol a street in Torreon, in the Mexican northern state of Coahuila, Monday, July 19, 2010. (AP Photo/Ramon Sotomayor)</em>

  • June 28, 2010

    Suspected cartel gunmen shot and killed a popular gubernatorial candidate in the northern state of Tamaulipas in the worst cartel attack on a politician to date. Rodolfo Torre, 46, and four aides from the opposition Institutional Revolutionary Party, or PRI, were ambushed on their way to a campaign event for the July 4 state election. <em>Caption: A billboard with the portrait of the candidate for Governor of Tamaulipas state for the Institutional Revolutionary Party (PRI), Rodolfo Torre, and reading 'A leader forever' is seen during his funeral at the Polyforum in Ciudad Victoria, Tamaulipas state, Mexico, on June 29, 2010. (LUIS ACOSTA/AFP/Getty Images)</em>

  • March 13, 2010

    Hitmen killed three people linked to the U.S. Consulate in Ciudad Juarez in March, provoking "outrage" from U.S. President Barack Obama. <em>Caption:The U.S. national flag flutters at half-mast at the entrance of the consulate of the United States in Ciudad Juarez, Chihuahua state, Mexico on March 15, 2010. (Jesus Alcazar/AFP/Getty Images)</em>

  • Jan 31, 2010

    Suspected cartel assailants killed 13 high school students and two adults at a party in Ciudad Juarez across from El Paso, Texas. <em>Caption: Students enter a high school in Ciudad Juarez, a city ridden by homicidal violence along Mexico's border with Texas. (Tim Johnson/MCT via Getty Images)</em>

  • Sept 15, 2008

    Suspected members of the Zetas drug gang tossed grenades into a crowd celebrating Mexico's independence day in the western city of Morelia, killing eight people and wounding more than 100. <em>Caption: From left to right: Julio Cesar Mondragon Mendoza, Juan Carlos Castro Galeana, and Alfredo Rosas Elicea, are members of a group of hitmen called the 'Zetas' shown to the press at the General Attorney's office in Mexico City, on September 26, 2008. The three gangsters confessed that they are the authors of a grenade attack that killed eight people during the celebration of Independence Day in Morelia, western Mexico. (STR/AFP/Getty Images)</em>