Five people were killed and dozens were injured when a vehicle bomb ripped through a busy street in the Colombian city of Cali on Thursday, local authorities said.
Police said the bomb had targeted the Marco Fidel Suarez Military Aviation School in the north of the city -- a fresh challenge to the country's fragile peace process ahead of 2026 elections.
"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. "Many houses were damaged in front of the base."
Several buildings and a school were evacuated.
Cali mayor Alejandro Eder said preliminary reports indicated at least five people were killed and 36 people were injured.
He announced a ban on large trucks entering the city, fearing further explosions, and a US$10,000 reward for information.
Eyewitness Alexis Atizabal, 40, indicated that civilians may be among the dead.
"There were fatalities among people passing by on the avenue," he said.
It was not immediately clear who was responsible, but regional governor Dilian Francisca Toro called it a "terrorist attack."
"Terrorism will not defeat us," she said.
In June, leftist guerrillas claimed responsibility for a wave of bomb and gun attacks in and around Cali that killed seven people.
The group, the Central General Staff (EMC), rejected a 2016 peace deal and has upped operations ahead of elections in 2026.
- Uptick -
Although guerrilla, paramilitary, and cartel groups still control swathes of Colombia, the country has enjoyed a decade or more of relative calm.
But there has been a recent surge in violence ahead of the 2026 presidential elections.
In a seemingly unrelated attack on Thursday, eight people were killed in clashes between guerrillas and police in the northwest of the country.
The police officers had been eradicating coca crops near the city of Medellin.
Many of Colombia's armed groups -- once based on leftist or rightwing ideologies -- fund themselves through the lucrative cocaine trade.
The attacks heap pressure on the government of President Gustavo Petro, whose conciliatory approach to armed groups has been blamed for the uptick in violence.
