The move comes just two weeks after hosts Tunisia crushed Djibouti 8-1 in their opening 2017 CAF Africa Cup of Nations qualifier. Leekens guided Tunisia to the 2015 Cup of Nations quarter-finals before suffering a defeat by hosts Equatorial Guinea.
An FTF statement read in part: "We have decided (on) an amicable separation between the two parties without any payment on the part of FTF or George Leekens." Leekens' contract with Tunisia was due to run until March 2016.