Colombia's FARC rebels fear reprisals by right-wing paramilitaries if they ratify a peace deal with the government, a commander said Monday, underscoring the trauma left by a bloody history of assassinations.

Speaking at a rebel conference to vote on the historic deal, Pablo Catatumbo, a member of the general staff of the Revolutionary Armed Forces of Colombia (FARC), listed guerrillas' various fears as they contemplate disarming and transitioning to civilian life.

Chief among them was the fear of revenge attacks by the remnants of right-wing paramilitary groups founded in the 1980s to fight them.

"There have been some concerns," Catatumbo said at the conference in El Caguan, the Marxist rebels' traditional stronghold in southeastern Colombia.

"A lot of people are worried about the paramilitary phenomenon."

As Colombia seeks to end a 52-year conflict that has claimed 260,000 lives and left 45,000 missing, it is haunted by the bloodstained demise of previous peace processes.

Particularly troubling for the FARC, whose leaders have agreed to relaunch as a political party if the deal is ratified, is the memory of a failed peace process in 1984.

Then, the FARC also agreed to set up a political party, the Patriotic Union (UP), in a step toward giving up its armed struggle.

But the peace process fell apart as paramilitaries assassinated some 3,000 of the party's members, including two presidential candidates, with secret backing from the state security forces.

The paramilitaries also carried out a scorched earth campaign against the FARC and their suspected supporters, sometimes wiping out entire villages.

The groups emerged because the growing momentum of the UP "scared the ruling class," said political analyst Luis Fernando Quijano.

"That led to the creation of the paramilitary groups, which teamed up with organized crime to annihilate the UP. And annihilate it they did," he told AFP.

Officially, the paramilitaries were disbanded from 2003 to 2006 as part of a demobilization process.

But the FARC says their remnants are still operating.

- New lives -

After nearly four years of peace talks in Cuba, FARC leaders must now convince their troops to endorse the 297-page deal concluded last month.

Some 200 FARC delegates, including 29 members of the general staff and delegates elected by the rank and file, will vote on the peace deal at the end of the six-day conference, which opened Saturday.

Catatumbo said the final vote would be by a show of hands, with a majority needed for it to pass.

Colombians are then due to vote on the accord in a decisive referendum on October 2.

If it passes, the FARC's estimated 7,000 fighters are to disarm in a process supervised by the United Nations.

Catatumbo said members have also voiced worries about finding their place in civilian life, getting their jailed comrades released and the trustworthiness of President Juan Manuel Santos's government.

"People are asking, for example... 'Will the government hold up its end of the deal? How will we be reintegrated into the national economy?' People are also worried about whether (FARC) prisoners will really be released," he said.

The deal offers a series of guarantees to sway the FARC rank and file.

Carrots for wary rebels include security guarantees, amnesty for "political crimes," reduced sentences for those who confess to other crimes and plans for the FARC's relaunch as a political party.

Catatumbo hastened to add that despite the concerns, the deal had broad support.

"In general, there has been unanimous support for the deal signed in Havana, for the commander in chief, the general staff and the negotiating team," he said.