Mexican marines captured the head of the ultra-violent Zetas drug cartel, Miguel Angel Trevino, an official from the federal attorney general's office told AFP.
"They carried out an important arrest, of Miguel Angel Trevino, in the early hours of Monday," the official said on condition of anonymity.
The Zetas are considered one of the most powerful and feared organized crime groups in Mexico, founded by former soldiers and known for their brutality.
Originally, the Zetas acted as the armed wing of the Gulf Cartel, but the two groups split in recent years, sparking brutal turf wars in the north of the country.
Trevino's capture comes eight months after Mexican troops killed his predecessor, Heriberto Lazcano, in a gunfight in the northern state of Coahuila, only to lose Lazcano's body hours later.
Last October, gunmen burst into a funeral home and stole his body, which has never been recovered.