The United States is seeking a "swift" extradition from Mexico of Nestor Isidro Perez Salas, or "El Nini," who is accused of heading security for the faction of the Sinaloa Cartel headed by the sons of founder Joaquin "El Chapo" Guzman, Attorney General Merrick Garland said on Thursday.

The Mexican National Guard on Wednesday captured Perez Salas. Viewed by U.S. anti-narcotics agents as one of the most ruthless Mexican drug figures, Perez Salas was detained in Culiacan, the Sinaloa Cartel's heartland, and was taken to Mexico City, according to government detention records.

"Shortly after the apprehension of El Nini, I spoke with Mexican Attorney General [Alejandro] Gertz [Manero] to thank him for the extraordinary efforts of the Mexican authorities who made the arrest," Garland said in a statement.

"We are now seeking El Nini's swift extradition from Mexico to face justice here in the United States."

The capture came less than a week after President Joe Biden met with Mexican counterpart Andres Manuel Lopez Obrador.

Perez Salas is accused by the U.S. State Department of working under Ivan Archivaldo Guzman to lead the "Ninis," a violent group of security personnel for the Guzman brothers, also known as "Los Chapitos."

U.S. courts have indicted Perez Salas on a slew of charges in relation to his alleged role at the helm of the Chapitos' security apparatus, including cocaine and methamphetamine trafficking conspiracy, possession of machine guns and witness retaliation.

The State Department had offered up to $3 million for information leading to his arrest.

In January, Mexican authorities captured Ovidio Guzman in Sinaloa and extradited him to the United States in September. The three other Guzman brothers who suspected of being leaders of Los Chapitos — including the figurehead, Ivan — remain free.