Tanks Used To Guard 'El Chapo' Over Escape Fears

The drug boss is being held in isolation and his door guarded 24-hours a day at the Altiplano prison, about an hour from Mexico City.

Armoured vehicles and light tanks sit outside the jail's walls and Mexican security forces guard sand-bagged checkpoints on surrounding roads.

Local media has reported that the cells in the prison have been fitted with electronic sensors and extra CCTV cameras.

The floor of Guzman's cell has also been reinforced using a mesh of steel bars, with officials determined not to allow him any escape opportunities.

But all of the security measures in the world may not be enough to comfort officials, with one source in the country's interior ministry saying that the main problem is that a prisoner such as Guzman could easily bribe the entire prison staff.

Six months ago, he staged a prison break that involved his gang obtaining plans to the prison and spending 17 months building a mile-long tunnel with a tiny rail system mounted with a motorbike.

The tunnel was dug right up into Guzman's cell and he was able to escape and ride the motorbike to freedom.

CCTV footage showed prison officials watching but doing nothing as the drug boss went behind a shower wall in his cell and disappeared into the hole in the floor.

A former director of the prison is among around two dozen people arrested in connection with the escape.

In 2001, Guzman paid-off guards to help him escape from a prison near Guadalajara after a previous arrest in 1993. It took 13 years for authorities to recapture him.

Jose Alfonso Carreon was the deputy director of the high-security jail in Tepic, similar to the one which Guzman escaped from, between 2000 and 2012.

He said the centres are "very secure", adding: "The only failures come via corrupting the personnel".

Guzman was arrested following his latest escape after Mexican marines tracked him to a house in Los Mochis, Sinaloa last Friday.

But even then he had not given up - escaping through a secret doorway in one of the house's bedrooms before reaching the city' underground drain system.

He was finally caught more than an hour later, as the build-up of rainwater in the drains forced him to emerge above ground.

Juan Pablo Badillo, one of Guzman's lawyers, said his client was "in a different, very cold zone (of the prison) and in complete isolation."

He added that Guzman, who has not yet been visited by family members, was physically very weak and had claimed he was being exposed to "brutal psychological pressure".

Senior Mexican officials spent four hours touring the prison and learning of its extra security measures on Sunday, with the country's National Security Commission saying that conditions in the jail "fully comply with international standards".

Moves are afoot to extradite Guzman to the US where he is wanted on charges including drug trafficking but this could take up to five years.