Colombia's government and leftist guerrillas argued Sunday over whether two police officers and a soldier captured by the rebels are hostages or prisoners of war.
The government delegation to peace talks here referred to them as kidnapping victims, and urged the FARC rebels to make good on their stated willingness to release them.
The three men were captured by the guerrillas on January 25.
"Each act like this is a direct attack on the peace process," said the head of the government delegation to the talks, Humberto de la Calle.
Colombia's conflict has dragged on for 50 years. These are the first negotiations in a decade.
The rebels meanwhile called the three captured men prisoners of war. The FARC has said it will release them to the International Committee of the Red Cross and a Colombian NGO.
Ricardo Tellez, considered as tantamount to foreign minister for the FARC, said the release of the three men is being prepared, and those two organizations have been told to report to the place where the men are being held.
He spoke as both sides concluded a fourth round of the peace talks, which began November 19 in Cuba's capital.