Commander Uriel, one of the main leaders of Colombia's left-wing National Liberation Army (ELN) rebels, was killed during a military operation, President Ivan Duque announced on Sunday.
"This is a particularly important blow (to the ELN) because one of the most visible figures of this terrorist organization has fallen," the president said in a speech in Choco department, in northwest Colombia where the operation took place.
According to the president, Andres Vanegas, 41, better known by his nom de guerre Commander Uriel, was responsible for kidnappings, murders and recruiting minors for his Marxist guerrillas.
He is also accused of being behind a car bomb attack on a police academy in Bogota in January 2019 which killed 21 recruits.
After that attack, Duque ended peace talks with the ELN that had been started by his predecessor, Juan Manuel Santos.
Attorney General Francisco Barbosa clarified that the death of the rebel commander had occurred during a "confrontation" with police in the jungle commune of Novita, during a military operation.
Active on social media, Uriel was one of the most high profile figures of the generational change within the ELN, an organization born in 1964 and led by guerrillas on average aged over 60.
The Choco region where Uriel operated is the scene of a turf war between the ELN and the Clan del Golfo, the largest drug cartel in the country.
It is a major exit point for cocaine exports to Central America and the United States and also an area of illegal gold extraction, whose income, according to prosecutors, exceeds that of drug trafficking.
The ELN, which is said to operate in about 10 percent of the country, has some 2,300 combatants and an extensive network of supporters in urban centers.
It is the last formal guerrilla group left in the country after the government reached a peace agreement with the larger Revolutionary Armed Forces of Colombia, or FARC, in 2016.