The collision happened on Boa Island Road on Monday afternoon.
Police said there are no details at the moment on the condition of the three people.
Earlier the Ambulance Service said there was a total of five casualties.
The road is expected to remain closed at Castlecauldwell Forest Park for a number of hours.
Anyone who witnessed the incident, which involved a silver Renault Megane and a silver Peugot 307, is asked to contact the PSNI in Enniskillen on 0845 600 8000.