US officials knew drug lord El Chapo planned to escape

SAN FRANCISCO -- The most powerful drug lord in the world, Joaquin "El Chapo" Guzman, is still on the run as a manhunt intensifying.

A nearly $4 million reward is now being offered to capture the dangerous kingpin, who escaped from a maximum-security prison in Mexico.

"The fugitive must have had help from personnel or officials from the prison," said Mexico's Interior Minister, after announcing the firing of three top prison officials.

ABC News has also learned El Chapo's sophisticated escape plan was at least six months in the making.

The mile-long tunnel, which was ventilated, led directly from his prison cell to a newly constructed home.

Officials say El Chapo, head of Mexico's Sinaloa Cartel, is responsible for tens of thousands of deaths by drug overdoses and murders.

His empire spans the globe and infiltrating 76 major U.S. cities.

White House Press Secretary Josh Earnest says the U.S. is offering full support to the Mexican government to aid in the capture.

The last time El Chapo escaped prison, he had the resources to hide for 13 years.

The DEA told ABC News that they had intelligence last year that he may have been planning this escape. But government officials in Mexico claim they were never warned.