Colombia and the Marxist FARC rebel group have agreed to extend a weapon hand-in deadline for guerrilla fighters by 20 days, President Juan Manuel Santos said on Monday, after logistical delays slowed parts of the group’s demobilization process.

The Andean country and the Revolutionary Armed Forces of Colombia (FARC) rebels signed a peace deal late last year to put an end to more than 52 years of war. The conflict, which also includes a smaller rebel group and paramilitary gangs, has killed more than 220,000 people.

Under the accord, rejected in a public referendum but pushed through by congress, all rebels are required to live in special camps around the country and hand in all their weapons to the United Nations, which is overseeing the demobilization process.

Rebel commanders, however, complained that the 180-day hand-in period, which expires May 30, would not be sufficient because of camp construction delays, including setting up sanitation and housing.