istanbul turkey foreign minister call syrian president bashar al-assad immediate removal friday say transitional government must establish voice support u.s. missile strike overnight one air base necessary oust regime soon possible leadership syria foreign minister mevlut cavusoglu tell reporters southern town alanya comment broadcast live want go transition government continue commit humanitarian crimes necessary step oust take say cavusoglu say safe zone civilians syria important ever say coalition inform u.s. missile strike speak phone french german foreign minister although say also say contact initiate russian foreign minister sergei lavrov u.s. secretary state rex tillerson turkish foreign minister say assad administration must remove