Bogota: Colombia will announce formal peace talks with its second-largest leftist rebel group, a government source told Reuters on Wednesday, moving the nation a step closer to ending the five-decade conflict.

The government and the National Liberation Army (ELN) have been in preliminary talks for over two years. The group recently freed two hostages, which President Juan Manuel Santos had demanded ahead of the start of formal talks.

‘The exploratory phase of the talks has finished and they have agreed to begin formal negotiations,’ the source from Colombia’s peace commissioner’s office told Reuters.

Cuba, Norway, Venezuela, Chile, Brazil and Ecuador will act as guarantor nations, the source said, adding that negotiations would be separate from those underway in Havana with the Revolutionary Armed Forces of Colombia, or FARC, the country’s largest Marxist rebel group.

Both organizations are considered terrorist groups by the United States and European Union.

Official talks would come as approval ratings hit new lows for Santos, who replaced former hardline President Alvaro Uribe in 2010. Now an opposition senator, Uribe has harshly criticized the FARC talks, which he says allow impunity for human rights violations.

Colombia has been negotiating with the FARC for over three years. Last week, the two sides failed to reach a self-imposed deadline for a final accord.

Uribe’s backers were furious at the idea that talks would go ahead while discussions with the FARC stretch on.

‘What shamelessness! The ELN makes money from kidnappings and immediately the government comes out to announce a peace process,’ Fernando Sierra, a lawmaker from Uribe’s right-wing Centro Democratico party, said in a tweet.

A joint announcement with the ELN will be made from Caracas, Venezuela, Colombia’s government said, without revealing what would be discussed. Media reported negotiations would take place largely in Ecuador.

The 2,000-strong ELN has increased oil pipeline bombings in recent months and continued kidnappings, in what many saw as an attempt to pressure the government into talks.

Inspired by Cuba’s 1959 revolution and established by radical Catholic priests in 1964, the ELN has battled a dozen Colombian governments since it was founded.

While many Colombians are suspicious of peace talks, they are tired of the violence that has killed more than 220,000 and displaced millions over the years.

‘The ELN peace process is magnificent news,’ Aida Avella, leader of the leftist Union Patriotica, which has historic ties to the FARC, said on Twitter. ‘We are heading to peace.’