"We're pleased by the extradition of Nelson Vargas Rueda out from Colombia to the United States," spokesman Richard Boucher said.

"This action underscores a strong degree of law enforcement cooperation between our two countries, as well as our commitment to bringing accused murderers of American citizens to face justice," he told reporters.

Vargas Rueda was transferred from the village of Combita to a police air base in Bogota on Wednesday where he was handed over to US Federal Bureau of Investigation (FBI) agents, according to Colombian officials.

He is to appear before a US district court in Washington, to be tried for his alleged role in the murders of Indian rights activists Terence Freitas, Ingrid Washinawatok and Lahee'Enay Gay, in March 1999.

Colombian President Alvaro Uribe authorized the extradition of Vargas Rueda, alias "The Pig," on May 7, a month after Colombia's Supreme Court validated the charges brought by the United States.

Freitas, Washinawatok and Gay were working in Colombia with the indigenous U'wa people when they were kidnapped by FARC members on February 25, 1999.

Their bullet-riddled bodies were found in a mass grave eight days later across the Venezuelan border.

The United States had asked Bogota to extradite Vargas Rueda and four other FARC members including fugitive German Briceno, brother of the FARC's number two official Jorge Briceno alias "Mono Jojoy."

WAR.WIRE