A new appeal has been made in the lengthy legal battle to halt the extradition of a notorious Mexican drug trafficker to the US.
Lawyers for Joaquin "El Chapo" Guzman approached a higher court after their appeal was rejected by a judge last month.
They argue that if he is extradited, he may face the death penalty in Texas.
However, Mexico agreed to transfer Guzman in May after the US guaranteed he would not face the death penalty.
Guzman, who was jailed for 20 years in Mexico in 1993, headed one of the most violent criminal organisations in Mexico, the Sinaloa Cartel, which is accused of supplying tons of drugs to the US.
He escaped twice from a maximum security prison, last being recaptured in January.
He faces many charges in the US, including drug trafficking and murder.
One of his lawyers, Jose Refugio Rodriguez, told AFP news agency the guarantee that he would not face the death penalty was not ironclad because it had been issued by the US embassy, not a US federal court.
According to another defence lawyer, Andres Granados, the new appeal could take between three and six months for a ruling.
Meanwhile, the defence team will lodge another appeal with the Supreme Court, Mr Granados was quoted by AFP as saying.
February 2014: Recapture after 13 years on the run following "laundry basket" escape from Puente Grande maximum security prison
July 2015: Escape via a 1.6km (one-mile) tunnel from Altiplano prison
2 October 2015: Interviewed by US actor Sean Penn in Durango state jungle hideout and then by phone and video
17 October: Mexican officials announce narrow escape as police try to recapture him in neighbouring Sinaloa state
January 2016: Recaptured in Los Mochis, Sinaloa state