OREANDA-NEWS. Lingering attacks on oil installations in Colombia could begin to wane as the government and the country's second-largest rebel group ELN open formal peace talks.

The ELN has historically attacked oil pipelines, installations and workers during its half-century armed conflict with the state.

Separate peace talks in Havana, Cuba with the largest anti-government rebel group Farc started in late 2012, and were supposed to have concluded with a final peace agreement on 23 March. Some differences between the two sides are still unresolved.

The ELN is known to be more ideological than the Farc and opposes private-sector participation in developing natural resources including oil.

Negotiators today signed an agreement in Caracas to pursue a six-point agenda, including social participation in peace-making, rights to political debate and expression, social programs to eradicate poverty and corruption, victims, and terms for ending the conflict.

"The agreement about the agenda that we've achieved with the ELN expressly says that… it will look for mechanisms of coordination with the Havana talks," Colombia president Juan Manuel Santos said.

The government-ELN negotiations will be held at a "public" forum in Ecuador, with additional sessions in Venezuela, Chile, Brazil and Cuba. These countries and Norway will act as guarantors of the talks.

The two parties held exploratory talks since January 2014 in Ecuador, Brazil and Venezuela.

Neighboring Venezuela is a key actor as Colombian rebels are known to operate in areas along Colombia's eastern border. The 220,000 b/d Ca?o Lim?n-Cove?as crude pipeline in eastern Colombia has been particular vulnerable to attacks for many years.

Venezuelan president Nicolas Maduro closed the Venezuelan border with Colombia in August 2015, and last month he vowed to keep it closed until Venezuela?s military eradicates smuggling and violent paramilitary groups.

Venezuela's defense ministry has long detected ELN participation in criminal activities inside Venezuelan territory.