Armed men in Colombia have killed 34 coca farmers in the north-eastern region of Norte de Santander.
Cocaine is a vital source of income for the Farc
A regional police commander Lt Col William Montezuma told the BBC that 50 gunmen rounded up the farmers in the village of Rio Chiquita and shot them.
The authorities blame the left-wing rebel group, Farc, for the attack, the worst since President Alvaro Uribe took office two years ago.
An official said the farm appeared to belong to right-wing paramilitaries.
Landless peasants often pick coca leaves and sell them to both left-wing guerrillas and their right-wing opponents, which can leave the farmers targets of reprisals.
Other villagers and farmers are now fleeing the area, fearful of further attacks, according to a human rights monitor.
The workers, who had been working at the farm for the past fortnight were sleeping in hammocks, when the gunmen arrived at dawn on Tuesday.
They were bound hand and foot with ropes and shot with automatic weapons.
Uribe came to power on a pledge to curb violence
"We saved ourselves by running toward the mountain,"
Jesus Bayona, 45, who survived after being shot in the foot, told the AP news agency.
President Uribe pledged to curb the violence which has plagued Colombia for decades, and increased military spending.
He is also trying to control the cocaine business, a key source of funding for armed groups.
"This is very bad, because we have called a safety council with
civilians and the military in the region to take measures to control
the violence in the area," local official Manuel
Alberto Luna told the AFP news agency.
On Friday, President Uribe is scheduled to start talks with the right-wing paramilitary group, the Self-Defence Forces (AUC), one of the main rivals of the Farc.