Colombia's FARC guerrilla group said Friday it was putting peace talks on pause to examine a government proposal that any peace agreement must be submitted to a national referendum.

President Juan Manuel Santos announced Thursday he was submitting legislation to Congress that would require a referendum on any peace agreement reached with the leftist rebels.

"In light of this new circumstance, the FARC's peace delegation has decided to make a pause in the talks to center itself exclusively on the implications of the government proposal," FARC negotiator Pablo Catatumbo said, reading from a statement.

The government and rebels have been holding peace talks in the Cuban capital Havana since November, with the aim of ending Latin America's longest insurgency.

Santos said that in the event of a peace deal, Colombians should vote on it when the country goes to either legislative elections or presidential elections.

Legislative elections are due in March 2014, and the presidential poll is set for May next year.

Catatumbo did not say how long the pause in the talks would last.

He noted that the rebels had previously proposed that a peace agreement be ratified by a national constituent assembly to give it the imprimatur of the people.

Although both sides have expressed optimism that an agreement can be reached, negotiators so far have dealt only with two of five topics on the agenda for the talks.

They reached a consensus on issue of rural development, and have been discussing the FARC's political reintegration.

Yet to be discussed are is the laying down of arms, drug trafficking and reparations for the victims of the conflict.

A government commission last month estimated that 220,000 people have lost their lives in the near 50-year-old conflict. Other estimates run as high as 600,000 dead.