Six former FARC fighters who were reintegrating into civilian life as part of the group's peace deal with the government, have been killed in an ambush in Isupi, in the southwestern department of Nariño.
Ramiro Cortes, a member of the Alternative Revolutionary Force Commons national leadership, the political party which the FARC transitioned into, said "They were part of the process. We know they were summoned to a meeting and that's when they were murdered last Sunday."
The dead men were Jose Miller Estupiñan Toloza, Carlos Sinisterra, Edinson Martínez Ordonez, Duber Alberto Obando Vallecilla, José Alfredo Garcia Estupinan, and another man called Johan, who has not been properly identified.
Initial reports said they died in a confrontation between FARC dissidents but the party's leadership has denied this.
The local director of the reintegration program, Aldemar Galan, said this is preliminary information and it is necessary to clarify the facts.
Galan said the incident shows the difficulties involved in implementing the agreements in the face of the Colombian government's refusal to accept its commitments, including the protection of former fighters as well as the social policies within the agreed zones.
At least 101 social leaders and activists have been killed between January and August 2017.
Earlier this week, Jose Jair Cortes, was murdered in a rural area of the Tumaco municipality in Nariño.
Jair Cortes, a member of the local council of the Alto Mira and Frontera Community, had received several death threats in recent months.
The governor of Nariño, Camilo Romero Galeano, denounced the murder which occurred just days after a massacre left seven people dead in the village of El Tandil, in the same municipality.