The Wall Street Journal, quoting an unnamed senior Mexican government official, said Cienfuegos was arrested at the request of the US Drug Enforcement Administration (DEA). Both spoke on the condition of anonymity because they were not authorized to discuss the case publicly. USA authorities did not warn their counterparts of the operation.
Mexico's foreign secretary, Marcelo Ebrard, confirmed the arrest via Twitter, writing that U.S. Ambassador to Mexico Christopher Landau informed him of Cienfuegos' detention. His family members were released and he was taken to the Metropolitan Detention Center.
He served under former President Enrique Pena Nieto, who was in office for six years until December 2018.
Mexico's former public security minister, Genero Garcia Luna, is awaiting trial in New York City on charges he accepted bribes from the Sinaloa drug cartel. Garcia Luna, who served under former President Felipe Calderón, has pleaded not guilty to drug trafficking charges.
The fall of Cienfuegos marks the first time a former defense minister has been arrested, and will have far reaching implications for Mexico's drug war, which has been led by the armed forces for more than a decade.
The Mexican investigative magazine Proceso, quoting unnamed sources at the US Department of Justice, reported that the arrest was the result of a long-standing US investigation named "Operation Godfather" into corruption involving drug traffickers.
"There were always allegations of corruption, nothing we could sink our teeth into". "If they cooperate (with US prosecutors) there are others who are going to be falling, noting USA officials "usually don't want to trade down, they usually trade up", seeking evidence against equal or higher-ranking officials". The minister claimed he received notice of the arrest from the U.S. Embassy in Mexico.
Lopez Obrador quickly incorporated the arrest into his narrative that predecessors had presided over a debilitating increase in corruption in Mexico, which for years has been convulsed by often horrific levels of drug gang violence. The army under his leadership, however, was accused of carrying out extrajudicial slayings of cartel members and human rights abuses.
The worst scandal in Cienfuegos' tenure involved the 2014 army killings of suspects in a grain warehouse.
Lopez Obrador said the general was "accused of links with drug trafficking", adding that the U.S. authorities were expected to give more details later Friday.