Rebecca Blackwell, File, Associated Press
FILE - In this Jan. 8, 2016 file photo, Mexican drug lord Joaquin "El Chapo" Guzman is escorted by soldiers to a waiting helicopter at a federal hangar in Mexico City, after he was recaptured from breaking out of a maximum security prison in Mexico. A Mexican judge said on Monday, May 9, 2016 that Guzman's extradition to the U.S. can move ahead, but the country’s foreign ministry must still approve it and the defense can appeal.

MEXICO CITY — A federal judge has ruled that the extradition of drug lord Joaquin "El Chapo" Guzman can move ahead, Mexico's Judicial Council said Monday. But the country's foreign ministry must still approve it and the defense can appeal.

The council, which oversees Mexico's federal judges and tribunals, said the judge, who it did not name, had agreed that the legal requirements laid out in the extradition treaty between the two countries had been met.

The ministry has 20 days to decide whether to approve Guzman's extradition to the United States.

Any extradition attempt can be delayed or stopped by a request to the court by attorneys for the Sinaloa cartel leader.

Guzman was moved Saturday from a prison outside Mexico City to one in Ciudad Juarez near the U.S. border. Questions have arisen on both sides of the border about the decision to relocate the convicted drug lord to a region that is one of his cartel's strongholds.

A Mexican security official acknowledged Sunday that the sudden transfer was to a less-secure prison.

The official said that in general the Cefereso No. 9 prison on the outskirts of Ciudad Juarez, across from El Paso, Texas, is not as impregnable as the maximum-security Altiplano facility near Mexico City where he had been held. The official wasn't authorized to discuss Guzman's case publicly and agreed to do so only if not quoted by name.

The official said, however, that Guzman is being held in a maximum-security wing where the same protocols are being enforced as in Altiplano, including 24-hour monitoring via a camera in his cell. Altiplano is considered the country's highest-security prison.

El Chapo" first broke out of another prison in 2001 and spent more than a decade on the run, becoming one of the world's most-wanted fugitives. He was recaptured in 2014, but slipped out of Altiplano, which many previously had thought was unescapable, in July 2015 by fleeing through a sophisticated, mile-long tunnel that went up into the shower in his cell.

Mexican marines re-arrested him in the western state of Sinaloa in January, after he fled a safe house through a storm drain.

He was returned to Altiplano, where he was placed under constant observation from a ceiling camera with no blind spots, and the floors of top-security cells were reinforced with metal bars and a 16-inch (40-centimeter) layer of concrete.

Some Mexican media have speculated that the weekend move was a prelude to imminent extradition to the U.S., where he faces drug charges in seven jurisdictions. But authorities denied that.

The security official said Guzman is still in the middle of the extradition process. The Foreign Relations Department has the final say, and Guzman's lawyers still have opportunities to appeal.

A lawyer for Guzman confirmed Saturday that his defense continues to fight the drug lord being sent to the U.S., and officials have said it could take up to a year to reach a final ruling.

Multiple analysts told The Associated Press that there was no sign of a link between the prison switch and extradition.