Convicted drug lord Joaquín “El Chapo” Guzmán, who twice pulled off brazen jailbreaks, was transferred to a prison in northern Mexico near the Texas border early Saturday.

Lawyers for Guzmán, who was recaptured in January, have filed multiple appeals against their client being sent to the US, and Mexican officials have said it could take as long as a year to reach a final ruling. There was no immediate indication that the transfer could be a sign that the process is nearing conclusion.

The Sinaloa cartel boss was moved from the maximum-security Altiplano lockup near Mexico City to a prison in Ciudad Juárez, across the border from El Paso, a security official said, without giving a reason for the transfer.

The official was not authorized to discuss the matter publicly and spoke on condition of anonymity. The Interior Department said the move was due to work being done to reinforce security at Altiplano.

Mexico’s National Security Commission said in a statement that the transfer was in line with security protocols, and it has rotated more than 7,400 inmates nationwide as part of a strategy implemented last September.

José Refugio Rodriguez, an attorney for Guzmán, confirmed that he was sent to the Cefereso No9 prison. He said Guzmán’s defense team was not notified beforehand, and one of his lawyers was traveling to Juárez to try to meet with their client.

“I don’t know what the strategy is,” Refugio said. “I can’t say what the government is thinking.”

Mexican security analyst Alejandro Hope called it plausible that Guzmán was moved due to upgrades being done at Altiplano, but said officials also may have feared the possibility of another jailbreak attempt.

“The more he remains at a single prison, in a single cell, the more the chances that he will rebuild the conditions that led to his escape,” Hope said. “So this also might be a deliberate attempt to destabilize any such plans.”

“The surrounding environment is risky because El Chapo certainly has a lot of people in Ciudad Juarez, so it seems like a relatively odd choice,” Hope said. “Probably the other alternatives were not any better, whatever their objective was.”

Michael Vigil, the former head of international operations for the US Drug Enforcement Administration, said Guzmán was moved because of security concerns. Vigil, who said he had been briefed by Mexican officials, did not specify those concerns or say whether Mexican officials had information about possible new escape plots. He also did not specify the officials with whom he spoke.

Guzmán faces charges from seven separate US attorneys’ offices, including in Chicago, New York, Miami and San Diego.

El Chapo first broke out of a Mexican prison in 2001. He was recaptured in 2014, only to escape the Altiplano lockup the following year through a mile-long tunnel dug to the floor of the shower stall 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 officials beefed up his security regimen. Guzmán 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 layer of concrete.