Colombia and the country's second-largest rebel group Wednesday that they will hold peace talks, heightening expectations for a definitive end to a half-century of political violence in the Andean nation

The government has been in exploratory talks in Ecuador with the National Liberation Army, or ELN, for more than a year. Negotiators for the two sides announced at a news conference in Caracas, Venezuela, that those talks will now be formalized around a six-point agenda, including justice for victims, disarmament, and reintegration into society.

While a start date has not been set, negotiations will kick off in Ecuador and then possibly continue in Venezuela, Brazil and Chile and Cuba. Those five countries, along with Norway, will sponsor the talks.

"If we can make peace, it will be the end of guerrilla fighters in Colombia and thus in Latin America," Colombian President Juan Manuel Santos said in a televised address to celebrate the breakthrough.

The government has been negotiating for three years in Havana with the largest Colombian rebel group, the far-stronger Revolutionary Armed Forces of Colombia, or FARC.

Santos emphasized that some important points have already been agreed upon in Havana and said will not be open for renegotiation in the new talks with the ELN, including the establishment of a post-conflict infrastructure to judge war crimes.

The smaller ELN, which the U.S. government classifies as a terrorist group, has an estimated fighting force of around 1,500 and relies on extortion and kidnapping to fund its insurgency. Its main base of operations is eastern Colombia, along the border with Venezuela, where it frequently bombs a major oil pipeline.

The group, founded by radical Roman Catholic priests in the 1960s, prides itself on being more ideologically pure than the FARC. Unlike the peasant-based FARC, the ELN shares a tradition with other leftist insurgencies in Latin America that were formed by urban students and intellectuals in the wake of the Cuban Revolution.

Many analysts say the same orthodoxy that led the ELN to shun a heavier involvement in Colombia's drug trade also blinded its commanders to the opportunity to negotiate a far-reaching deal.

In recent weeks, the group kidnapped a local councilman and captured an army sergeant. Both were later freed but the group is believed to still be holding several others for ransom. On Wednesday, Santos called such actions "unacceptable" and incompatible with the peace drive.

The ELN, for its part, has played down its involvement in criminal activity.

"We didn't start this peace process to talk about kidnapping," the guerrilla commander known by the alias Antonio Garcia told journalists at a rare news conference in Caracas. "We're here to seek solutions to Colombia's problems."

Colombia's civil war has killed an estimated 200,000 people.

Human rights groups greeted news of the talks with cautious optimism, but stressed the importance of punishing all those who have committed abuses during the long-running conflict.

"The talks between the ELN and the government, coupled with an imminent peace deal with the FARC, bring hope that more than half a century of conflict in Colombia might soon be over," said Erika Guevara-Rosas, Americas director at Amnesty International. "The government and the ELN must ensure that human rights, including measures to put an end to impunity, lie at the heart of the negotiations."

Associated Press | By LIBARDO CARDONA and FABIOLA SANCHEZ