For the first time, Colombia on Thursday extradited two alleged members of the National Liberation Army (ELN) who are accused by a U.S. federal court of drug trafficking.

Extradition is one of the toughest tools Colombia and its allies use to try to combat the production and distribution of cocaine.

The Andean country – under constant pressure from the United States to reduce production of coca and cocaine – has sent hundreds of its citizens north over the last three decades to face drugs charges, including members of the now-demobilized FARC rebels and paramilitary gangs.

The men extradited on Thursday are Henry Trigos Celon and Yamit Picon Rodriguez, who uses the alias Chonta, both wanted by the Southern District of Texas, Colombian Justice Minister Wilson Ruiz said in a statement.

Trigos is accused of storing and distributing drugs in Norte de Santander province, along the border with Venezuela, while Picon allegedly served as head of finance for the ELN’s Northeastern front and conducted business with Mexico’s Sinaloa cartel.

The men were handed over to U.S. authorities at an air base in Bogota belonging to Colombia’s national police.

The ELN, former FARC members who reject a 2016 peace deal and crime gangs formed by former right-wing paramilitaries are all involved in drug trafficking in Colombia, where a nearly six-decade conflict has killed 260,000 people.

The ELN – which has some 2,500 fighters and is classed as a terrorist organization by the United States and European Union – has previously denied involvement in the drugs trade but has admitted coca cultivations and cocaine labs are present in the areas where it operates.

TodayNG