CHICAGO — A son of notorious Mexican drug kingpin “El Chapo” pleaded guilty Friday to U.S. drug trafficking charges, becoming the first of the drug lord’s sons to enter a plea deal.

Prosecutors allege Ovidio Guzman Lopez and his brother, Joaquin Guzman Lopez, ran a faction of the Sinaloa cartel. They became known locally as the “Chapitos,” or “little Chapos,” and federal authorities in 2023 described the operation as a massive effort to send “staggering” quantities of fentanyl into the U.S.

As part of a plea agreement, Ovidio Guzman Lopez admitted to helping oversee the production and smuggling of large quantities of cocaine, heroin, methamphetamine, marijuana and fentanyl into the United States, fueling a crisis that has contributed to tens of thousands of overdose deaths annually.

Guzman Lopez pleaded guilty to drug trafficking, money laundering and firearms charges tied to his leadership role in the cartel. Terms of the deal, including sentencing recommendations or cooperation agreements, were not immediately disclosed.

Speculation about a deal had percolated for months, as behind-the-scenes negotiations quietly progressed.

Jeffrey Lichtman, an attorney for the two brothers, said Friday he would wait until Ovidio Guzman Lopez was sentenced before discussing whether the agreement was a good deal.