MEXICO CITY — The U.S. ambassador to Mexico has confirmed that drug lord Ismael “El Mayo” Zambada was brought to United States against his will when he arrived in July on a plane in Texas with fellow drug lord Joaquin Guzman Lopez.

Zambada’s attorney had earlier claimed the long-time chief of the Sinaloa cartel had been kidnapped. But officials had not confirmed that and Zambada’s age and apparent ill-health had led some to speculate he turned himself in.

But on Friday, U.S. Ambassador Ken Salazar said “they had brought El Mayo Zambada against his will.” Salazar said no U.S. personal, resources or aircraft were involved in the flight on which Guzman Lopez turned himself in.

In early August, Zambada made his second appearance in federal court in Texas after being taken into U.S. custody last week.

Guzman Lopez, one of the sons of notorious drug kingpin Joaquin “El Chapo” Guzman,” landed at an airport near El Paso on July 25. Both men were arrested and remain jailed. They are charged in the U.S. with various drug crimes.