Mexico has sent drug lord Rafael Caro Quintero, who was behind the killing of a U.S. DEA agent in 1985, to the United States with 28 prisoners requested by the U.S. government, a Mexican government official and other sources confirmed Thursday.

It comes as top Mexican officials are in Washington trying to head off the Trump administration's threat of imposing 25% tariffs on all Mexican imports next week.

The official, who requested anonymity because they were not authorized to discuss the case, confirmed Caro Quintero's removal. Another person familiar with Mexico's actions also confirmed the removal on the condition of anonymity because they were unable to discuss sensitive diplomatic negotiations.

Mexico's Attorney General's Office said in a statement that the 29 prisoners sent to the U.S. Thursday faced charges related to drug trafficking and other crimes.

Also among the list were two leaders of the Los Zetas cartel, Mexicans Miguel Trevino Morales and his brother Omar Trevino Morales, known as Z-40 and Z-42, the official confirmed.

The removal of the drug lords from Mexico coincided with a visit to Washington by Mexico's Foreign Minister Juan Ramon de la Fuente and other top economic and military officials. The meeting was the latest in ongoing negotiations with the U.S. over trade and security relations, which have radically shifted since U.S. President Donald Trump took office.

The bilateral talks come just days before the March 4 deadline set by Trump to apply broad 25% tariffs on Mexican imports, which economists say would thrust the Mexican economy into recession.

In exchange for delaying tariffs, Trump had insisted that Mexico crack down on the U.S.-Mexico border, cartels and fentanyl production, despite significant dips in migration and overdoses over the past year. The removals may indicate that negotiations are moving along as the tariff deadline approaches.

Caro Quintero had walked free in 2013 after 28 years in prison when a court overturned his 40-year sentence for the 1985 kidnapping and killing of U.S. Drug Enforcement Administration agent Enrique "Kiki" Camarena. The brutal murder marked a low point in U.S.-Mexico relations.

Caro Quintero, the former leader of the Guadalajara cartel, had since returned to drug trafficking and unleashed bloody turf battles in the northern Mexico border state of Sonora until he was arrested by Mexican forces in 2022.

The removal of the Trevino Morales brothers also marks the end of a long process that began after the capture in 2013 of Miguel Trevino Morales and two years later of his brother, Omar. The process wound on for so many years that then-Mexico's Attorney General Alejandro Gertz Manero described the lags as "truly shameful."

The Trevino Morales family, who have been accused by American authorities of running the violent northeastern Cartel from prison, have charges pending in the U.S. for participation in a criminal organization, drug trafficking, firearms offenses and money laundering.