(CNN) -- Marxist rebels killed seven police officers in a roadside ambush in southwestern Colombia, officials said.
A top rebel leader also was believed to be killed in a separate attack, said army Gen. Gustavo Adolfo Ricaurte.
Juan Carlos Usuga, known as El Enano (The Dwarf), was among at least 25 guerrillas killed by a joint police and air force task force that destroyed a rebel camp in the Amazonian jungle, Ricaurte said.
The six police agents and a lieutenant died in a roadside blast on their return from inspecting the rebel stronghold, which the air force had bombed, said Cauca Gov. Guillermo Alberto Gonzalez.
But an army officer at the scene told CNN affiliate Caracol TV that the men were attacked with a grenade and high-caliber rifle fire.
There has been heavy fighting in the area between the task force and rebels from the Revolutionary Armed Forces of Colombia, known by its Spanish acronym, FARC.
The attack occurred Monday, Ricaurte said.
The truck in which the police had been riding was part of a convoy returning to the city of Cali from a jungle FARC camp that had been destroyed. Authorities said they found a radio base, armaments, supplies and documents at the camp.
A video on Caracol shows a large hole blown through the truck's windshield. Some weeping family members were shown at a government building where the bodies were taken.
Authorities said Tuesday that the FARC and local drug traffickers coordinated the attack.
The remote area has become "a corridor" for drug runners, Gonzalez said.
The FARC has been fighting the Colombian government for more than 40 years, and has major strongholds in the jungles of southwest Colombia.
Drug traffickers also have strongholds in the area and often are allied with the FARC, which provides security and intelligence.