Mexican authorities say they have arrested Jose Maria Guizar Valencia, the alleged leader of the Zetas drug cartel.

National Security Commissioner Renato Sales identified the suspect only as "Jose Maria," but a federal official who was not authorized to be quoted by name confirmed Guizar Valencia's name.

Guizar Valencia is a U.S. citizen also known by his Zetas code name, "Z 43." 

The United States had offered a $5 million reward for his arrest.

Sales said Guizar Valencia was arrested Thursday in Mexico City's trendy Roma neighborhood, which is known for its restaurants and cafes.The commissioner said the leader was one of the main generators of violence and had directed Zetas' drug trafficking and other activities in southern Mexico.

Under a "Wanted" page online, the U.S. Bureau of International Narcotics and Law Enforcement Affairs said Guizar Valencia is "responsible for the importation of thousands of kilograms of cocaine and methamphetamine to the United States on a yearly basis" and faces separate U.S. drug trafficking indictments in Texas and Virginia.

It also said he had taken over territory in neighbouring Guatemala.

'Working in concert but independently'

"Los Zetas, under the command of Guizar Valencia, have murdered an untold number of Guatemalan civilians during the systematic overtake of the Guatemalan border region with Mexico during recent years," the bureau said.

Playa del Carmen

"This is to show that we are here, that Phillip-BPM didn't get in line," read a message claim responsibility for the massacre. (Semanario Playa News Aquí y Ahora (Translates: the Weekly Beach News Here and Now/Facebook))

The bureau also said Guizar Valencia was born in Tulare, Calif.

The Zetas are one of Mexico's most violent and feared cartels. Originally recruited from the ranks of the Mexican and Guatemalan armies as foot soldiers and bodyguards to the Gulf Cartel, they turned on their employers and became a cartel of their own.

Formed by deserters of an elite military unit, the Zetas is known for indiscriminate brutality, filling anonymous graves and roadsides with piles of victims' bodies. 

A faction calling itself "Old School Zetas" last year claimed a massacre at the BPM music festival in Playa del Carmen, as its own when it hung two painted signs on thoroughfares there.

The Zetas' leadership has been decimated by the arrest and deaths of main capos in recent years, and the once fearsome cartel has splintered into several factions.

Even before that, the bureau said Guizar Valencia was "considered his own entity, working in concert but independently" of the main Zetas faction.