Two separate attacks blamed on dissident guerilla groups killed 18 people and wounded dozens in Colombia, one involving a truck bomb while a drone downed a police helicopter in the other, deepening the country's most serious security crisis in decades.
The latest deadly attacks, which struck the southwestern city of Cali and a coca farm in the north, pose fresh challenges to Colombia's fragile peace processes ahead of elections next year.
A truck loaded with explosives was detonated on a busy street near a military aviation school in Cali, killing six people and wounding more than 60, officials said.
"There was a thunderous sound of something exploding near the air base," 65-year-old eyewitness Hector Fabio Bolanos told AFP.
"There were so many injured people," he said.
Images shared on social media showed vehicles on fire, destroyed homes, injured people on the ground and people fleeing in panic amid the sound of alarms and screams.
The mayor of Cali, Alejandro Eder, ordered martial law for the country's third most populous city. He also announced a temporary ban on large trucks entering the city and called on the public to report information about the incident for a $10,000 reward.
Defence Minister Pedro Sanchez blamed the attack on the Central General Staff (EMC) guerrilla group, led by warlord Ivan Mordisco.
The group broke away from the defunct Revolutionary Armed Forces of Colombia (FARC) after it agreed to lay down arms for a historic peace deal in 2016.
