Disaster relief authorities are rushing to a Colombian town where more than a dozen people have been reported killed when a flash flood swept away ramshackle homes in the dead of night.

The massive flooding triggered by heavy rains early Monday in the town of Salgar.

Media reports say 500 people lived in the path of the ravine that broke its bank and as many as 45 people had been killed. Authorities on the scene have not yet issued a report of casualties.

President Juan Manuel Santos ordered authorities to provide immediate assistance to those affected.