Colombia's criminal gangs pose the biggest threat to Colombians and are responsible for human trafficking, rights abuses and for forcing tens of thousands of people to flee their homes each year, the United Nations said.
While the government holds peace talks with leftist rebels of the Revolutionary Armed Forces of Colombia (FARC) in a bid to end 50 years of civil war, the main security threat to the Colombian people comes from organized crime - often perpetrated by ex-paramilitary fighters, according to a U.N. report.
Criminal gangs, composed of former right-wing paramilitaries and common criminals, are bent on maintaining and expanding their stakes in the cocaine trade and in illegal gold and silver mining along Colombia's Pacific coast.
“The main public security challenge remains violence by post-demobilization armed groups linked to organized crime,” said the annual human rights report released on Monday.
“Violence affects the rights of those living where such groups dispute control of illicit revenues derived from the drug trade, extortion, illegal mining, prostitution, trafficking in persons and illegal migration.”
Five decades of fighting between government troops, leftist guerrillas and right-wing paramilitary groups have uprooted six million Colombians and killed more than 200,000.
The rise of new powerful criminal gangs stems partly from the failure of the demobilization of paramilitary groups.
A 2003 peace accord led to more than 35,000 paramilitary fighters handing in their weapons but thousands have since returned to crime and violence, forming new criminal groups which still hold sway in their traditional strongholds.
“There aren't any examples of successful demobilization processes in the world. In Colombia, it wasn't a great success,” Todd Howland, head of the U.N. human rights office in Colombia, told reporters in Bogota.
The report said criminal gangs linked to organized crime are threatening community leaders and human rights activists trying to restore land seized by armed groups to its rightful owners.
Last year, 45 human rights campaigners were murdered in Colombia, of whom 11 had previously received death threats.
“Frequent death threats against land activists and related impunity should be firmly addressed,” the report said.
The government says it is providing nearly 2,000 activists with free protection, including bodyguards and bullet-proof vests and cars.
Fighting between warring factions and gang crime continue to force people from their homes in huge numbers - the report said an average of a quarter of a million people had been uprooted each year since 2010.
Around half of all displaced Colombians live in the cities, many settling in makeshift shelters in slums, often with no land tenure rights and no drinking water.
Police arrested more than 1,000 gang members last year, but the U.N. report said the government needed to do more to combat corruption and provide young people with job opportunities to discourage them from joining crime rings.