MEXICO CITY -- Mexican authorities said Saturday they have filed formal charges against alleged drug kingpin Edgar "La Barbie" Valdez Villareal and are weighing a request to extradite him to the United States.

The Texas-born Valdez, considered one of Mexico's top drug traffickers in recent years, faces charges including drug trafficking, kidnapping and arms possession, according to a statement issued by the Mexican Attorney General's Office.

He also now faces a formal extradition process based on a U.S. warrant for drug-trafficking charges in Louisiana, the statement said.

Valdez, who had been held pending charges since his Aug. 30 arrest, is described by authorities as a former ally of Mexico's most-wanted kingpin, Joaquin "El Chapo" Guzman, and he allegedly had been fighting for control of the Beltran Leyva gang after Mexican marines killed its leader in late 2009.

The warring factions have been blamed for brutality and bloodshed south of Mexico City, from Cuernavaca to the Pacific coast state of Guerrero, which includes the resort city of Acapulco.

It's not clear in which country Valdez will be tried first. Mexico has increasingly extradited high-profile drug suspects to the U.S. under President Felipe Calderon as a way to prevent them from running cartels from corrupt Mexican prisons.

His U.S.-based attorney, Kent Schaffer, said both he and the U.S. Justice Department want Valdez to be prosecuted in the United States, where he is wanted on cocaine-smuggling charges in three states.

Valdez was transferred to a federal prison in Toluca near Mexico City to await the outcome of his case. Schaffer said Mexican authorities had agreed to transfer Valdez to a prison in the border city of Matamoros, across from Brownsville, Texas, in anticipation of his extradition -- then went back on their word.

Schaffer said Friday he fears for Valdez's safety in the Toluca prison.

The Mexican Attorney General's Office declined to comment on his statement.