The lawyer said he suspects the government is seeking to violate Guzman's due process by speeding up his extradition
Mexico's government moved closer on Thursday to its goal of extraditing notorious drug lord Joaquin "El Chapo" Guzman to the United States by February, after a judge rejected an appeal.
The attorney general's office said in a statement that a tribunal in Mexico City ruled against Guzman. But his lawyer immediately told AFP he would appeal the ruling to a higher court.
The Foreign Ministry had approved the Sinaloa drug cartel chief's extradition in May, but his lawyers fought the decision in district court.
The tribunal in the capital, which had been reviewing the case since September 26, "decided to reject the protection" sought by Guzman, the attorney general's office said.
One of Guzman's lawyers, Andres Granados, said he would pick up court documents on Tuesday and from then he would have 10 business days to appeal to a "college" of judges.
He also vowed to seek a Supreme Court hearing.
"We are not defeated," Granados told AFP, adding that he could still take the case to the Inter-American Commission on Human Rights.
The lawyer said he suspects the government is seeking to violate Guzman's due process by speeding up his extradition.
Guzman was recaptured in January, six months after his brazen escape from a maximum-security prison through a 1.5-kilometer (one-mile) tunnel that opened into his cell's shower.
The national security chief, Renato Sales, said last week that the government hopes to extradite Guzman by January or February.
A US government official has told AFP that the extradition process could finish earlier, by the end of this year.
Guzman is facing two extradition bids, one in California for drug distribution and another in Texas on charges that include murder and money laundering.
Guzman's extradition would set up a major trial in the United States for the head of a cartel accused of providing tons of drugs to addicts in the United States while fueling violence in Mexico.
Guzman was captured in February 2014 after 13 years on the lam, but he escaped a year later from a maximum-security prison near Mexico City, humiliating President Enrique Pena Nieto.
After the slippery drug kingpin was recaptured in January in his northwestern home state of Sinaloa, Pena Nieto demanded his speedy extradition.
The president had balked at extraditing Guzman before his July 2015 escape, preferring to put him on trial in Mexico.
Guzman was returned to the same prison he had escaped from near Mexico City, but in May he was abruptly transferred to a penitentiary in Ciudad Juarez, a city bordering the US state of Texas.
His name was again in the news earlier this week after a federal judge who had analyzed one of his appeals was shot in the head in broad daylight as he jogged in Metepec, near Mexico City.
Another Guzman lawyer, Carlos Castillo, rejected any links between his client and the murder Monday.
While the judge, Vicente Antonio Bermudez, had analyzed Guzman's case, he did not issue a ruling, Castillo said.
Bermudez's court, based in the State of Mexico, also reviewed other cases related to drug traffickers.