BOGOTA (Reuters) - The amount of planted coca, the raw material used to produce cocaine, rose in Colombia last year for the first time since 2007, including in several rebel strongholds, according to a UN report on Wednesday that is likely to fan criticism of the government.
One of the world's top cocaine producers, Colombia, has been battling drug-funded leftist rebels and powerful gangs for decades, but billions of dollars in drugs still leave the nation each year despite a decade-long U.S.-backed security crackdown.
The area planted with coca increased 3 percent to 64,000 hectares (158,147 acres) in 2011 versus the previous year, the U.N. Office on Drugs and Crime said in its yearly report on Colombia's drug business.
The number, however, was still far below the 163,000 hectares (402,781 acres) planted in 2000 when the United States began spending billions of dollars to combat drug traffickers and guerrillas.
Despite the increase, production of cocaine decreased 1 percent last year to 345 tonnes versus 2010, which the United Nations attributed to lower productivity.
The figures will likely give fodder to political rivals of President Juan Manuel Santos, especially former President Alvaro Uribe, who want to paint Santos as out of touch with security problems on the ground. In 2010, Santos succeeded Uribe, who was barred by the constitution from running for a third term.
"It will certainly add fuel to the fire of the Uribistas, who are relentlessly criticizing Santos," said Cynthia Arnson, Latin American program director at the Woodrow Wilson Center.
"But some of the security advances of the Uribe years are reflected in these U.N. statistics. Pushing the guerrillas into remote border areas has served to reinforce the nexus between coca-cultivation and rebel activity. The relationship between the two was never really broken or taken care of by Uribe."
Santos has seen his ratings slide in recent weeks partly due to complaints that rebels - who are largely funded by the drugs trade - were gaining the upper hand against government troops after hard-fought battles over the last decade.
In an interview with Reuters, Santos rejected accusations that guerillas from the Revolutionary Armed Forces of Colombia, or FARC, were making a comeback, describing recent attacks as a last-gasp effort to grab headlines that did not pose a threat to economic prosperity.
The largest increases in coca plantings were in the Putumayo and Caqueta provinces near the border with Ecuador - regions where the state is historically weak and FARC rebels maintain a strong presence.
More than 60 percent of planted areas are located in only four departments - Narino, Putumayo, Guaviare and Cauca - where the Marxist guerrillas and former right-wing paramilitaries-turned-drug-lords fight for control over routes.
"That area has always been pretty ungoverned, it is basically wired for getting drugs out," said Adam Isacson of the Washington Office on Latin America.
"The 2011 results make apparent that momentum toward reduced coca-growing has once again stalled."
U.N. officials played down the overall increase, calling it "statistically insignificant". Twenty-three of Colombia's 32 provinces grow the crop.
"About 56 percent of cultivators are selling their coca leaves, which tells us something very important: that the others are assuming roles in the production of their coca to cocaine," said Leonardo Correa of the U.N. anti-drugs office.
Reporting by Katherine McKeon & Ignacio Badal; Editing by Jack Kimball and Paul Simao