Colombia's FARC rebels on Wednesday said one person was believed killed in fighting last week between their forces and renegade members opposed to a historic peace deal with the government.
The violence threatens to disrupt delicate efforts by leaders of the communist rebels and the government to push through a peace accord to end a nearly 53-year conflict.
Commanders of the FARC's Southern Bloc said in a statement the violence erupted on January 10 near the southern central town of San Vicente del Caguan.
"There was an armed confrontation between units of this bloc and a squad led by Alexander Mojoso, who resolved to abandon our ranks on the grounds that he disagrees with the current peace agreement between President Juan Manuel Santos' government and the FARC," it said.
"In the clash, one member of Mojoso's group is said to have been killed."
After more than five decades of territorial and ideological conflict with the government, the FARC is due to start disarming in the coming weeks under UN supervision.
The Colombian conflict grew out of a crushed peasant uprising in the 1960s.
It has killed more than 260,000 people and left 60,000 missing.
It has drawn in not only the army and the FARC, but other leftist rebel groups, drug gangs and right-wing paramilitary units.
Last October, voters rejected the peace deal after opponents condemned the concessions made to the FARC.
The deal allows the FARC to transform into a political party.
The opposition campaign complained that Santos granted the rebels seats in Congress, saying he should have jailed them for war crimes instead.
Santos, who won the Nobel Peace Prize five days after the referendum defeat, sent his negotiators to work out a revised deal with the FARC.
The second time around, he had it ratified in Congress. He has warned that delaying implementation of the accord raises the risk that fresh violence will break out.
