BOGOTA (Reuters) - Colombia’s Marxist FARC rebels can begin surrendering their weapons to the United Nations now that almost 7,000 of them have reached designated demobilization zones around the country, President Juan Manuel Santos said on Monday.

The Revolutionary Armed Forces of Colombia (FARC) signed a peace agreement with the government late last year to put an end Latin America’s longest-running armed conflict, which killed more than 220,000 people.

The rebels will have turned in all their arms by June, Santos said.

“This weekend the process of mobilization toward the zones was completed and the protocols of the bilateral and definitive ceasefire and the abandonment of arms has begun,” Santos said in southern Putumayo province.

Over the past weeks, FARC rebels crisscrossed Colombia on foot and by boat from their jungle and mountain camps to 26 zones monitored by U.N. personnel.

Under the terms of the peace accord, the FARC, which began as a peasant uprising 52 years ago, is to form a political movement in the South American nation.

The accord has been heavily criticized by many, and was initially rejected in a referendum, as being too lenient on the rebels who will be spared jail time.