(CNN) -- A high-ranking rebel leader who opposed peace talks with the Colombian government has been captured, authorities said.
Carlos Marin Guarin, known by the alias "Pablito," commanded roughly half the force of the National Liberation Army, a Marxist insurgent force known by its Spanish initials, ELN, according to a statement Tuesday from the Colombian government.
"This is perhaps the most important capture done by the army of any military leader of the National Liberation Army in its history," said Colombian Defense Minister Juan Manuel Santos.
Formed in the early 1960s, the ELN is the second-largest insurgent force in Colombia, behind the Revolutionary Armed Forces of Colombia, or FARC. The ELN is part of a long-running war that involves leftist rebels, right-wing paramilitary forces, the Colombian government and drug traffickers.
The government contends Guarin's capture in the capital of Bogota is significant because of his opposition to peace negotiations with Colombian authorities.
"We know that on several occasions he prevented [other rebel leaders] from signing a peace deal with the Colombian government," the defense minister said, according to a statement on a Colombian government Web site.
Authorities blame Guarin for the death of a bishop, an attack on a Venezuelan military base near the Colombian border that killed eight soldiers, kidnappings and blasts on parts of an oil pipeline on more than 200 occasions, the statement said. E-mail to a friend