TEGUCIGALPA, Honduras — In a blow to President Juan Orlando Hernández of Honduras, American prosecutors on Monday announced drug charges against his younger brother, describing him as a “large-scale drug trafficker” who spent a dozen years moving cocaine shipments bound for the United States through Central America.

Juan Antonio Hernández, 40, was deeply involved in all aspects of the drug trade — arranging security and protection for shipments, taking bribes from traffickers, and assuring government contracts for money-laundering front companies — according to Geoffrey S. Berman, the United States attorney in Manhattan.

Mr. Hernández was so established in trafficking, prosecutors said, that he had even had his own cocaine brand: Laboratories in Colombia and Honduras stamped packets with the initials T.H., for Tony Hernández.

He was arrested in Miami on Friday, but American officials did not provide details until Monday. The first confirmation of the arrest came from President Hernández himself on Friday, in a statement from his office that reaffirmed his government’s commitment to justice and declared that no one was above the law.