Mexico's most notorious drug lord, Joaquin "El Chapo" Guzman, broke out of a high security prison on Saturday night for the second time, escaping in a tunnel built right under his cell, and heaping embarrassment on President Enrique Pena Nieto.      
The kingpin snuck out of the prison through a subterranean tunnel more than 1.5 km (1 mile) long that ended in a building site in the local town, National Security Commissioner Monte Alejandro Rubido told a news conference on Sunday.
Guzman, who had bribed his way out of prison during a previous escape in 2001, was seen on video entering his shower area at 8.52 p.m. on Saturday (9.52 p.m. ET), then disappeared, the National Security Commission (CNS) said.
Wanted by U.S. prosecutors and once featured in the Forbes list of billionaires, Guzman was gone by the time guards entered his cell in Altiplano prison in central Mexico, the CNS said.
"This is going to be a massive black eye for Pena Nieto's administration," said Mike Vigil, former head of global operations for the U.S. Drug Enforcement Administration.
"I don't think they took into account the cunning of Chapo Guzman and the unlimited resources he has. If Chapo Guzman is able to make it back to the mountainous terrain that he knows so well in the state of Sinaloa ... he may never be captured again."
Beneath a 50 cm (20 inch) by 50 cm hole in the cell's shower area, guards found a ladder descending some 10 meters (32 feet) into the tunnel, which was about 1.7 meters (5.6 feet) high and 70-80 centimeters (28-31 inches) wide.
Prison workers were quickly detained over the escape.
Rubido said 18 officials from the penitentiary had been taken in for interrogation at the unit specializing in organized crime at the Attorney General's office.
Security services called a meeting of their top officials, ordered a massive manhunt for El Chapo, or "Shorty", and shut down the airport in the nearby city of Toluca.
Guzman became one of the world's top crime bosses, running the powerful Sinaloa Cartel, which smuggled billions of dollars worth of cocaine, marijuana and methamphetamines into the United States and fought vicious turf wars with other Mexican gangs.
The flight of Guzman, who became an almost legendary figure in villages scattered in the sierra where he grew up in northwestern Mexico, seriously undermines Pena Nieto's pledge to bring order to a country racked by years of gang violence.
U.S. Attorney General Loretta Lynch, noting Guzman faces multiple drug trafficking and organized crime charges in the United States, said Washington shared Mexico's concern over the escape.
"The U.S. government stands ready to work with our Mexican partners to provide any assistance that may help support his swift recapture," she said in a statement. 

The breakout happened in the State of Mexico, the home state of Pena Nieto, who took office in 2012 vowing to confront cartel violence that has killed more than 100,000 people since 2007. 

The Mexican president has come under increasing pressure to deliver on his pledges to root out corruption after becoming embroiled in a string of conflict-of-interest scandals. He was en route to France when news of Guzman's getaway broke.
Before Pena Nieto won election, politicians in his Institutional Revolutionary Party (PRI) had mocked their conservative rivals for letting Guzman escape while they ran the country, saying it would not have happened on their watch.
Days after Guzman was captured in 2014, Pena Nieto said another El Chapo escape must "never happen again."
"Given what happened in the past, truly, it would be worse than deplorable, it would unforgivable," he said then.

Inside the passage used for Guzman's latest escape, guards found a motor bike mounted on rails probably used to cart off soil, Rubido said, as well as equipment to aerate the tunnel.

He did not comment on why authorities had apparently failed to notice a long tunnel being built under the prison.
The capo's escape could also strain relations with the United States, which wanted him extradited, said Alberto Islas, a security expert at consultancy Risk Evaluation.
"They were concerned about how dangerous he was, and they had a lack of confidence in the Mexican authorities to stop him operating from jail," he added.
In 2001, Guzman paid guards to help him slip out of the high security Puente Grande prison near the city of Guadalajara following a previous arrest in 1993. After eluding capture for 13 years, Guzman was arrested in February 2014 in his home state of Sinaloa.
Government officials vowed on Sunday that Guzman would be recaptured, and security forces fanned out to search roads near the prison, which is some 90 km (60 miles) west of the capital.