The explosion, which happened at about 3am local time, tore through a crowded city street in Florencia, located about 335km south of Bogota, slaying revellers who had been enjoying the Zona Rosa district’s dance halls and restaurants.
Two police officers who were patrolling the area were among the dead. The blast also killed a 12-year-old boy and a girl had a leg amputated in hospital, officials said.
“Everything indicates the FARC terrorist group carried out the attack,” Luis Ardila, commander of the 12th Army Brigade in Florencia told Reuters. He was referring to the Revolutionary Armed Forces of Colombia, a Marxist guerrilla army known as “FARC.”
“There were three pubs still open and people were leaving to go home when the bomb went off. There were a lot of people in the street.”
Florencia, the capital of the lawless Caqueta province, is near a former demilitarized area the government handed over to FARC rebels to hold peace talks that eventually collapsed.
In February, FARC rebels kidnapped three civilian US Defense Department contractors when their light aircraft crashed on a hillside near Florencia, while on a mission to spy out drug crops.
The FARC says the Americans are "prisoners of war" and is holding them hostage somewhere in the jungle.
Sunday's bomb attack was a blow to President Alvaro Uribe's efforts to rein in indiscriminate violence in a war that claims the lives of thousands of people every year.