At least nine Colombian police officers were killed and three others wounded on Saturday morning when a helicopter carrying them crashed in the northeastern province of Casanare, the National Police said.

The aircraft crashed into a mountainous area because of an apparent mechanical problem just a few minutes after taking off from the town of Salinas, said the police.

The officers were being transported to another place as part of a routine police personnel change, they added.

The names of the dead officers were yet to be released.

The injured were swiftly flown to hospitals in Casanare's capital Yopal, and in the neighboring province of Boyaca