The body of Colombian regional governor Luis Francisco Cuellar has been found only hours after he was dragged from his home in the state of Caqueta.
The Colombian authorities say left-wing FARC rebels were responsible.
It is the first attack on a high profile politician since President Alvaro Uribe came to power in 2002.
President Alvaro Uribe gave his reaction:
“There are still some that want to give political recognition to the narco-terrorist FARC group, it is good that the international community understands these actions… what the FARC do, the suffering that they have put Colombia through for almost 50 years, it leaves only room for one adjective… terrorists.”
Cuellar’s body was found bound and gagged with several bullet wounds. Explosives had been placed around him.
A series of recent defeats at the hands of Colombian security forces was thought to have weakened the rebels.