The Mexican military captured the leader of the Gulf Cartel on Saturday in north-eastern Mexico, the government said, dpa reported.
Mario Armando Ramirez Trevino, alias El Pelon or X-20, was caught in a joint operation of the army and the navy in Rio Bravo of Tamaulipas state.
Ramirez Trevino is reportedly a former police officer. He previously led the armed wing of the Gulf Cartel, Los Rojos.
After the capture of his predecessor Eduardo Costilla in September and a series of internal power struggles, he assumed leadership of the cartel, Milenio newspaper reported.
The US Drug Enforcement Agency has offered a 5-million-dollar reward for information leading to his capture.
The Gulf Cartel is one of the oldest crime syndicates in Mexico. It became synonymous with drug trafficking and violence in northern Mexico, but has lost influence in recent years after the split of its former security arm, Los Zetas in 2010.
Los Zetas has meanwhile become Mexico's most powerful cartel, and the Gulf and Sinaloa cartels have joined forces to fight its influence.