"In all honesty, we have to inform the public that at this time there are major differences with the FARC on substantive issues," the negotiator said at a Wednesday press conference following peace talks in Havana.
Last month, Colombian President Juan Manuel Santos issued an ultimatum for FARC to conclude a peace deal by March 23.
FARC chief negotiator Ivan Marquez said on Wednesday that the group had presented the government with a "roadmap" for the cessation of hostilities in the country. Marquez expressed hope that the roadmap would be agreed at the next round of peace talks with the government.
The FARC rebel group was established in 1964 as the military wing of Colombia's Communist Party. Since then, military confrontation between FARC and the Colombian government has been ongoing, with over 200,000 people having been killed as a result.
The two sides have been engaged in peace talks since November 2012 and have reached a number of important agreements including on landmine removal, land reform, transitional justice and an end to illegal drug trafficking.
Last year, Santos and FARC signed a deal in Havana that set the schedule for the rebels’ full demobilization and disarmament.
Earlier this month, the Colombian president said that the signing of a peace agreement between the government and FARC could be delayed, in which case he was ready to propose to create another deadline.
