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 on the US border, in a move that appears to bring him closer to extradition to the US.
Guzman, 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 penitentiary in central Mexico through a 1.6km-long tunnel.
Chapo, or "Shorty", faces charges ranging from money laundering to drug trafficking, kidnapping and murder in cities that include Chicago, Miami and both Brooklyn and Manhattan, New York.
His lawyer, Juan Pablo Badillo, said Guzman was moved early on Saturday, but he was not sure why.
"It's an absurd action, illogical," said Mr Badillo.
"The authorities shouldn't do this. It was totally unexpected."
Guzman's lawyers will meet to plot a course of action, Mr Badillo added.
"At this moment, he can't be extradited," said Mr Badillo, noting that the legal process is not yet finished.
Eduardo Sanchez, a spokesperson for Mexico's presidency, said Guzman's transfer to the state of Chihuahua was due to upgrades at his previous location, the Altiplano jail in central Mexico, and not part of an effort to deport him to the United States.
However, a senior Mexican security official said Guzman should be extradited before July and would probably be housed initially in the US prison in Marion, Illinois, pending trial.
"I think they'll do it in the first half of this year," the official said, speaking on condition of anonymity.
A Chihuahua state official, who also asked to remain anonymous, said the presence of a US consulate in Ciudad Juarez meant Guzman's handover could be processed faster than through the US embassy. He said he believed Guzman would be moved to the United States in a matter of weeks.
Just across the border from Ciudad Juarez is the US Fort Bliss military base, where Guzman could be taken.
Earlier this year, Reuters reported that prosecutors in El Paso, the city on the other side of the border from Ciudad Juarez, had staked a claim to try Guzman if he is extradited.
Other US attorneys' offices with cases against Guzman will also bid to try him first after extradition.