A Colombian air force plane carrying 125 people crashed just after takeoff deep in the country's southern Amazon region, with one dead and 77 people hospitalised, authorities said.
Colombian president Gustavo Petro said one person was killed and 77 have been hospitalised.
The country's defence ministry said a Lockheed Martin Hercules C-130 plane crashed on take-off.
Defence Minister Pedro Sanchez said the crash happened as the plane was taking off from Puerto Leguizamo, deep in Colombia's southern Amazon region on the border with Peru, as it transported troops.
"The exact number of victims and the causes of the crash have not yet been determined," he said.
Colombian Air Force Commander Fernando Silva said in a video posted on social media that the plane was carrying 114 passengers and 11 crew members and that authorities were still investigating the cause of the crash.
Footage it shared from the scene showed thick plumes of smoke rising from the wreckage.
A spokesperson for US defence company Lockheed Martin said the company extended its condolences to those affected by the crash and that it was committed to helping Colombia as it investigates the incident.
"I hope there are no fatalities in this horrific accident that should never have happened," President Gustavo Petro said in a post on X, in which he criticised bureaucratic obstacles for delaying his plans to modernise the military.
"I will grant no further delays; it is the lives of our young people that are at stake," he said. "If civilian or military administrative officials are not up to this challenge, they must be removed."
Hercules C-130 planes were first launched in the 1950s and Colombia acquired its first models in the late 1960s.
It has more recently modernised some older C-130s with newer models sent from the US under a law that allows for the transfer of used or surplus military equipment.
Details of the plane involved in the crash were not immediately available.
At the end of February, another Hercules C-130 belonging to the Bolivian Air Force crashed in the populous city of El Alto, barely missing a residential block.
More than 20 people died and another 30 were injured, and banknotes from the plane's cargo scattered around the city, prompting clashes between residents and security forces.
