Colombia’s largest rebel group, the Revolutionary Armed Forces of Colombia (FARC), has acknowledged its actions “have affected civilians” during 50 years of internal conflict.
“We are expressly responsible for all acts of war carried out by our units,” said Pablo Atrato, a FARC leader.
In the first admission of its kind, he said the rebels were ready to take “responsibility” for these actions.
Latin America’s longest running war has killed 220,000 people.
More than five million others have been displaced.
The Marxist rebel group joined negotiations in Cuba with the Colombian government in November 2013.
The talks in the capital, Havana, are aimed at getting the 8,000-strong FARC to sign an agreement renouncing its armed struggle in order to join the legal political process.
“We explicitly recognise that our actions have affected civilians at different times and under different circumstances throughout the conflict,” Mr Atrato said.
He added the FARC would “assume the responsibility that concerns us,” but did not give any further details as to what responsibility they would take.
The FARC’s statement comes as both sides discuss the issue of victim reparations as part the peace talks.
The two sides have reached agreement on three key issues: land reform, political participation of the rebels and illicit drugs.
They are now working towards agreements on disarmament, victims’ rights and the eventual implementation of the peace deal.
They are expected to attempt to negotiate an amnesty as part of the deal but correspondents say it would face opposition from conservative politicians in Colombia.
President Juan Manuel Santos recently said his government and the rebels were getting closer to an agreement.
The FARC, Colombia’s largest guerrilla group, controlled nearly a third of the country a decade ago, but now mostly operates in remote rural areas.