Colombia’s anti-government guerrillas have grown stronger under President Gustavo Petro’s three years in office.

An attack on a Colombian National Police helicopter and a suspected car bombing near a military air base left at least 19 people dead Thursday in what Colombian authorities are describing as terrorist acts.

CALI, Colombia (AFP)-Colombia on Friday promised to counter the threat from "desperate" armed groups after twin guerrilla attacks killed 19 people and deepened the country's worst security crisis in decades.