Mexico's most wanted drug boss Mario Cardenas Guillen, alias "El Gordo" - the Fat One - has been arrested by Mexican Marines.
An alleged leader of the Gulf Cartel, one of the largest drug trafficking rings in the world, El Gordo was arrested in Altamira in the northern state of Tamaulipas near the border with Texas.
El Gordo was armed when he was apprehended.
The weapon was confiscated together with two grenades, 129,700 pesos (£6,000) in cash and plastic bags containing a white powder.
After the arrest, El Gordo was paraded before the media flanked by two armed marines wearing balaclavas.
The arrest is a blow to the cartel, which is embroiled in a bloody war with government forces as well as with rival gang Los Zetas.
Guillen was "one of the main leaders" of the Gulf Cartel, said military spokesman Jose Luis Vergara.
"This is certainly a big hit to the cartel but historically new leaders are tapped very quickly," Vicente Sanchez, a security researcher with the Northern Border University in Tijuana, said.
According to Mexican officials El Gordo became boss of an autonomous faction of the cartel after his brother Antonio Ezequiel - known as "Tony Tormenta" - was shot dead in a gunfight with marines in 2010.
Following the death of Tormenta the Gulf Cartel split in two groups, one led by El Gordo and another by Jorge Eduardo Costilla - "El Coss".
President Felipe Calderon launched a war on drug cartels in 2006 which has resulted in the detention or deaths of 22 of Mexico's 37 most wanted drug traffickers.
About 60,000 people have died in the war on drugs.