By Jeremy McDermott
BBC News, Medellin
The largest demobilisation of Colombia's right-wing paramilitaries has begun.
More than 2,000 AUC members are handing over their weapons
More than 2,000 members of the United Self-Defence Forces of Colombia (AUC) are delivering their arms and entering programmes to re-enter civilian life.
The aim of the country's president, Alvaro Uribe, is to demobilise all of the 15,000-strong AUC before the end of this administration.
The AUC is considered one of the most brutal of the warring factions.
The process has begun in the town of San Roque near Medellin, and rifles and machine guns are piled up on the tables of the government peace commissioner, Luis Carlos Restrepo.
However, nobody is certain whether peace or a reduction in violence in this war-torn country is actually moving any closer.
The demobilisation of the Heroes of Granada bloc of the AUC symbolises all that is uncertain in the peace process.
Of the 2,000 fighters handing in their weapons, most are from the city of Medellin and many from the underworld organisation known as The Office of Emvigado, a criminal network that dates back to the days of Pablo Escobar and the Medellin drug cartel.
The Emvigado has long provided assassination services and resolves disputes between drug traffickers.
These men have little to do with the right-wing paramilitaries, except that their boss, Diego Murillo, who has also demobilised, became a paramilitary warlord after the fall of the Medellin drug cartel and is reputed to be one of Colombia's top drugs traffickers.
So what many observers fear is that this paramilitary peace process is simply wiping the criminal records of some of the country's most unsavoury characters and leaving them free to continue their criminal enterprises but with a clean slate.