Colombia's ELN rebels say they have not agreed to ceasefire

FILE PHOTO: Colombian President Gustavo Petro speaks to journalists about his government's first 100 days, in Bogota

BOGOTA (Reuters) - A ceasefire announced over the weekend by Colombian President Gustavo Petro is a proposal to be discussed at peace negotiations and is not in force, the National Liberation Army (ELN) rebel group said on Tuesday.

Petro, himself a former guerrilla, has pledged to end the Andean nation's six-decade internal conflict, which has left at least 450,000 dead. His government held a first round of peace talks with the ELN in December.

Over the weekend Petro said Colombia would hold a six-month ceasefire with the ELN and four other armed groups.

"The negotiations delegation of the ELN has not discussed with the government of Gustavo Petro any proposal for a bilateral ceasefire, so there exists no agreement on that issue," the ELN said in a statement posted on its website.

The December meeting in Caracas covered only the installation of the negotiation and its agenda, the ELN said, adding that the next cycle in Mexico is also set to cover the talks' agenda.

"Once we finish (that issue) it is predicted we will be available to discuss the bilateral ceasefire proposal, to examine the terms to make a deal possible," the rebels added.

Petro's office said it had no immediate comment, but that the president would meet with the government's high peace commissioner and officials in the Interior and Defense ministries.

The government said over the weekend that it would issue a decree for each armed group with specific conditions for the ceasefire and that the ceasefire would be verified by the United Nations, among others.

Previous attempts at negotiations with the ELN, which has some 2,400 combatants and was founded in 1964 by radical Catholic priests, have not succeeded partly because of dissent within its ranks.

Rebel leaders have said the group is united, but it is unclear how much sway negotiators hold over active units. Much of the ELN's negotiating team is older than many of its members.

(Reporting by Luis Jaime Acosota and Julia Symmes Cobb; Editing by Paul Simao)