The CIA has helped the Colombian army kill at least two dozen guerrilla leaders with the Revolutionary Armed Forces of Colombia - or FARC - as part of a secret program, The Washington Post reported Sunday.

The plan to decimate the leadership of the FARC, an active guerrilla organization that is currently in its most vulnerable period during its decades-long insurgency against the Colombian government, was authorized by former U.S. President George W. Bush in the early 2000s, the daily said.

The joint program has been continued by President Barack Obama, according to U.S. military, intelligence and diplomatic sources cited by the paper.

The secret aid to combat the FARC has a budget of millions that is kept separate from the $9 billion in U.S. military aid to Bogota known as Plan Colombia, which was begun in 2000.

The FARC, which took up arms against the Colombian government 50 years ago, was once considered "the best-funded insurgency in the world," the Post said.

The paper based its reporting on interviews with more than 30 U.S. and Colombian officials from current and former administrations and the majority of the interviewees made their statements under conditions of anonymity.

The anti-insurgency program has been aimed at attacking leaders not only of the FARC but also of the National Liberation Army, or ELN, a smaller Colombian guerrilla group, the paper said.