Mexican drug boss Joaquin “El Chapo” Guzman has been moved from a jail in central Mexico to a prison in Ciudad Juarez, a northern city located on the U.S. border, but the move was not a prelude to extradition, authorities said Saturday.

Eduardo Sanchez, the spokesman for the president’s office, said Guzman’s transfer was due to upgrades at his current location, the Altiplano jail, and not part of initial efforts to deport him to the United States.

Guzman, the head of the Sinaloa drug cartel, was one of the world’s most wanted drug kingpins until his capture in January, six months after he broke out of a high-security jail in central Mexico.

His lawyer, Juan Pablo Badillo, said Guzman was moved on Saturday night, but was not sure why.