Around 300 fighters from Colombia’s Marxist FARC rebels will not demobilize under a peace deal, a military commander said, giving the first official figure of guerrillas who may join with crime gangs seeking control of lucrative rebel drug territory.

The Andean country and the Revolutionary Armed Forces of Colombia (FARC) rebels agreed late last year to end more than 52 years of war. Colombia’s conflict with guerrilla groups and paramilitaries has killed more than 220,000 people.

The figure is the first official estimate of how many rebels will not demobilize. More than 6,000 FARC fighters are set to finish arriving at UN camps in the coming days to hand over weapons and begin reintegration programs.

Some rebel commanders, especially from units dedicated to drug trafficking or illegal mining in rural jungle areas, have rejected the peace deal and refused to lay down arms.

FARC leaders expelled five dissenting commanders in December.

“The FARC has acknowledged some dissent,” General Alberto Jose Mejia told Reuters this weekend, listing six fronts that have rejected the deal.