Two days after drug lord Joaquin "El Chapo" Guzmán was transferred to a prison near Juárez, a Mexican city near the U.S. border, a federal judge in Mexico said the extradition process can move forward.

An unnamed judge said the "legal requirements laid out in the extradition treaty" between the U.S. and Mexico had been met, The Associated Press reports, adding that Mexico's foreign ministry has 20 days to approve the extradition.

NPR's Carrie Kahn reported in January that Guzmán had been "indicted on drug and arms trafficking, money laundering and murder charges in at least six U.S. states." In July 2015, Guzmán escaped from Mexico's supermax Altiplano prison through a mile-long tunnel. He was recaptured in January.

But the judge's go-ahead for extradition is one step in what could still be a lengthy process. Lawyers for Guzman can still try to block or delay any attempts to extradite the infamous leader of the Sinaloa cartel.

As the Two-Way has reported, the head of Mexico's extradition office, Miguel Merino, warned in January that Guzmán's legal team could pursue various appeals that could delay the drug kingpin's extradition for four to six years.

Reuters reports that "Juan Pablo Badillo, one of Guzmán's lawyers, said his client's legal situation was still being processed and that to extradite him now would be a violation of his human rights." The news service adds that "government officials have said in private that the decision to extradite the drug lord is essentially a political decision dependent on the president."

The Dallas Morning News spoke to former FBI agent Arturo Fontes, who followed Guzmán's movements for 28 years. Fontes said the decision to transfer Guzmán to Juarez, a city he called one of the kingpin's "strongholds," could mean one of two things:

"Either the Mexican government really intends to ship him out to the United States immediately, or something else is afoot," he said. "There are no coincidences here. I'm not buying the government's explanation. For the sake of the Mexican government, they need to extradite him ASAP or risk being a joke again."

NPR's John Burnett reports that Mexican officials say Guzmán was moved to the prison near Juarez while Altiplano was upgrading security. He adds:

"The governor of Chihuahua State — where Chapo is now locked up — told reporters on Saturday, 'There is no risk of an escape.'"U.S. justice officials have been saying privately they expect Guzman to be brought to the United States to stand trial in Brooklyn for cocaine trafficking. Mexican officials did not mention a possible extradition — only that the wily trafficker would be more secure in Juarez."

Copyright 2016 NPR. To see more, visit http://www.npr.org/.