MEXICO CITY (REUTERS) - Mexican security forces on Saturday caught the leader of the cocaine-trafficking Gulf Cartel, the second major gang boss capture in just over a month.

Mario Ramirez Trevino, known as X-20 or "The Bald One", was captured in Mexico's northern Tamaulipas state, according to a government statement. Ramirez had not long been the leader of the Gulf Cartel, whose former boss Jorge Costilla, alias "El Coss", was caught in September.

The Gulf Cartel's power has waned in recent years in a feud with Mexico's most brutal gang, the Zetas, which began life providing protection to the cartel's operations in north-eastern Mexico.

The United States government had offered a US$5 million (S$6.35 million) bounty for Ramirez, as Washington said his cartel controls most of the cocaine and marijuana trafficking to the US from Matamoros in Tamaulipas state. Mexico's marines last month arrested the leader of the Zetas, Miguel Angel Trevino, a few kilometres from his hometown of Nuevo Laredo on the US border.

More than 70,000 people were killed during former president Felipe Calderon's six-year offensive against drug cartels, and over 6,000 have died since Mr Enrique Pena Nieto took office in December.