Cali (AFP)

Colombia's defense minister vowed on Friday to defeat "desperate" armed groups after twin terrorist attacks killed 19 people and deepened the country's worst security crisis in decades.

Minister Pedro Sanchez huddled with top security officials in the tropical city of Cali, where a truck bomb exploded on a busy street killing six and wounding 60 on Thursday afternoon.

Although the vehicle-mounted cylinder bombs detonated near a military aviation school, all of the victims were civilians, the authorities said.

Just hours earlier, guerrillas in the northwest of the country used rifles and drones to down a police helicopter, leaving 13 officers dead.

Despite the attacks, Sanchez claimed the military was making inroads against armed groups on several fronts.

"The impact on criminal groups has been to drive them to a state of desperation" he said.

Sanchez said that in five areas of operation, extortion, murders and child recruitment had fallen, so "they attack with the most criminal and insane weapon that exists: terrorism."

President Gustavo Petro's government has blamed both attacks on guerrilla groups.