The Colombian government and the leftist Revolutionary Armed Forces of Colombia (FARC) continue to try to wrap up an expected peace deal that would put a definite end to South America's longest-running armed conflict.

But the FARC and Bogotá are still at odds over some key issue, including the guerrillas' demand to establish a demilitarized zone to safely demobilize the group's fighters, as well as the government's insistence to hold a plebiscite, in which Colombian citizens would have to approve a final agreement, according to Colombia Reports.

The government rejected the proposal to establish the so-called "Terrepaz" areas, in which FARC wants to exercise a level of autonomy and begin its transformation from a guerrilla group to a non-violent political movement, the website noted.

Gen. Jorge Enrique Mora, one of Bogotá's top negotiators, flatly rejected the idea, noting that such zones "exist only in the imagination" of the rebels.

"We have never considered a fragmented Colombia, it doesn't fit in our imagination," Mora said. "It had not occurred to us."

Meanwhile, FARC leaders again blasted the plebiscite proposal in a statement, alleging the idea had never been brought up in the Havana-based negotiations with the Colombian government, the semi-official Venezuelan news network Telesur reported.

"That instrument of popular participation, has no binding capacity; it was slipped into the agreements in Havana," said the FARC in a statement released on their website.

"The item was never considered in the talks. It is alien to the agenda. It produces no legal certainty nor are we committed to it," the militant group insisted. "Such an instrument cannot tie the fate of the final peace agreement. Doing so would be a disaster."

However, in a goodwill gesture toward the rebels, the government of President Juan Manuel Santos, for the first time this week declined to extradite to the United States a FARC member accused of drug trafficking, The New York Times noted.

Juan Vicente Carvajal, who is wanted by American prosecutors, is thus unlikely to face justice in an American courtroom, the newspaper said.