On Wednesday, Colombia’s Ministry of Defence confirmed that it captured in a dawn raid Luis Alberto Cortés Bueiticá, alias Culebro Viejo, commander of the guerrilla’s Eastern Front and trusted confidant of Gustavo Aníbal Giraldo, alias Pablito, a senior member of the National Liberation Army’s (ELN) Central Command. 

The capture took place on Venezuelan soil, in the state of Apure, which borders the Colombian oil-rich department of Arauca, and where the ELN maintains an important presence. The guerrilla commander was located after information was exchanged between Colombia’s judicial police (Dijin) and Venezuela’s National Anti-Drug Office (ONA). Cortés is the alleged mastermind of several explosions that rocked the Colombian capital last year and faces charges that include murder, drug-trafficking, extortion, forced displacement and forced disappearances.

On Monday, the Colombian military killed a member of the ELN during a gunfight in the department of Casanare, just 17 days before formal peace talks with the rebel group are slated to begin.

The army said Monday that it had ambushed and exchanged gunfire with a group of rebels who had allegedly been extorting cattle ranchers, farmers, commercial drivers and business owners in the departments of Arauca, Boyacá and Casanare.

“ the individuals, which prompted a gunfight between the soldiers and members of the illegal armed group, resulting in the death of a terrorist in the course of the military operation, the capture of four individuals and the rescue of two minors,” the Colombian military said in a statement.

It is unclear how the clash will affect peace talks with ELN, the country’s second largest guerrilla group, which are set to begin on Nov. 3 in Quito, Ecuador.

The two parties had not agreed to a ceasefire.

President Juan Manuel Santos had called for ELN to reach an agreement with the government “as soon as possible,” a move ELN has rebuked.

“We express disagreement with the prospect of an ‘express’ peace process, because this cannot advance with tight time limits,” ELN said on its Twitter account on Monday.

The gunfight Monday occurred near La Salina, a mountainous village in the department of Casanare located 155 miles northeast of Bogotá.

There are an estimated 2,500 ELN rebels in Colombia, mainly living in rural areas. Santos had suspended talks with the group in May after the high-profile kidnapping of Spanish journalist Salud Hernández-Mora.

The announcement of formal peace talks with ELN boosted optimism after the rejection on Oct. 2 of a peace accord with the Revolutionary Armed Forces of Colombia (FARC), the country’s largest rebel group, plunged the country into a political crisis.

Santos said the Colombia’s peace process “will be complete” if it includes ELN, but the recent military offensive seem to be striking ever-closer to the guerrilla’s central command.