A truth commission to probe abuses during Colombia's half-century-old conflict should be held after, not before, peace is reached with leftist rebels, Bogota's top negotiator said on Sunday.

Humberto de la Calle's remark was the first reaction from the government to a proposal that was raised eight months ago by the Revolutionary Armed Forces of Colombia, or FARC, in talks between the two sides to resolve their differences.

"There can be no end to the conflict without truth," said de la Calle, a former Colombian vice-president.

The government of President Juan Manuel Santos sees such a commission as "a real instrument for peace and not as a tactical tool for negotiations", he said.

The FARC, a leftist guerrilla group, has been at war with the state since 1964. Considered Latin America's longest-running insurgency, the fighting has left hundreds of thousands dead and has displaced 4.5 million.

President Santos said on Saturday that troops of the government killed a finance officer with the FARC and vowed to press ahead with offensives against the guerrilla group despite peace talks.

John Hernandez, alias "Fabian", who was head of finance for FARC, was killed by government soldiers in a hamlet in the south of the country, Santos said.

Progress made on drugs

De la Calle's comments came as both sides headed into an eight-day break in closed-door talks in the Cuban capital, Havana, that began in November 2012. FARC guerrillas and negotiators for the government said in a joint statement that they "have advanced substantially" on aspects of the talks focused on illegal drugs.

Lead FARC negotiator Ivan Marquez also thanked former Colombian president Ernesto Samper (1994-98) for suggesting that Colombia could accept Guantanamo detainees - as Washington has requested - in exchange for the release of two FARC commanders imprisoned in the United States on drug trafficking charges.

The opposition has repeatedly asked for the release of Simon Trinidad, one of the jailed commanders, so that he can participate in the peace talks, which have been underway without a cease-fire.

Separately, a marine was killed in Colombia on Sunday and five others wounded when rebels ambushed their patrol in the southern province of Narino, the Colombian navy said.

In the southwestern valley of Cauca, the Colombian army said, soldiers confiscated 1.2 metric tons of marijuana belonging to rebels in a stash hidden in a cane field.

(China Daily 04/01/2014 page10)