Colombian President Juan Manuel Santos has publicly acknowledged the government's role in the killings of leftist activists in the 1980s.
During a ceremony at the presidential palace Thursday, Santos apologized to surviving members of the Patriotic Union party (UP). Some wearing shirts with the saying "They can cut the flowers, but they can't stop the birth of spring."
"That tragedy should have never happened and we must recognize that the government didn't take sufficient measures to impede and prevent the assassinations, attacks, and other violations even though there was evidence the persecution was taking place," Santos said in front of 200 survivors and family members of UP.
Some 3,000 people were killed by paramilitary groups during peace talks between the government and UP members in the 1980s, which Colombians frequently refer to as political genocide.
"The persecution of the members of the Patriotic Union was a tragedy that led to its disappearance as an organization and caused untold damage to thousands of families and our democracy," Santos said.
The president's speech comes less than two weeks before he is scheduled to sign a peace accord with the Revolutionary Armed Forces of Colombia - FARC. The agreement is the end of a civil war that has killed more than 220,000 people and displaced millions. Some 7,000 FARC fighters will be incorporated into society and permitted to form a political party.
On Monday, FARC rebels apologized for the "great pain" they caused by kidnapping thousands of people to fund half a century of conflict through ransoms.
FARC said in a video recording late Sunday that it had taken captives over the years but would not do so again.
Some 27,000 people were kidnapped between 1970 and 2010, according to official figures. As many as 90 percent of those were seized by the FARC.
The rebel group amassed a fortune from kidnappings, extortion and the drug trade.
The two sides are scheduled to sign the peace agreement on September 26. The deal will then be put to a vote on October 2, allowing Colombians to decide whether to accept the accord.