diff --git a/Installation/include/CGAL/Installation/internal/enable_third_party_libraries.h b/Installation/include/CGAL/Installation/internal/enable_third_party_libraries.h
index 9375f7229b1..1e4f7bb3ca0 100644
--- a/Installation/include/CGAL/Installation/internal/enable_third_party_libraries.h
+++ b/Installation/include/CGAL/Installation/internal/enable_third_party_libraries.h
@@ -27,11 +27,11 @@
 
 #if defined(__has_include)
 #  if CGAL_USE_GMP && ! __has_include(<gmp.h>)
-#    warning "<gmp.h> cannot be found. Less efficient number types will be used instead. Define CGAL_NO_GMP=1 if that is on purpose."
+#    pragma CGAL_WARNING(<gmp.h> cannot be found. Less efficient number types will be used instead. Define CGAL_NO_GMP=1 if that is on purpose.)
 #    undef CGAL_USE_GMP
 #    undef CGAL_USE_MPFR
 #  elif CGAL_USE_MPFR && ! __has_include(<mpfr.h>)
-#    warning "<mpfr.h> cannot be found and the GMP support in CGAL requires it. Less efficient number types will be used instead. Define CGAL_NO_GMP=1 if that is on purpose."
+#    pragma CGAL_WARNING(<mpfr.h> cannot be found and the GMP support in CGAL requires it. Less efficient number types will be used instead. Define CGAL_NO_GMP=1 if that is on purpose.)
 #    undef CGAL_USE_GMP
 #    undef CGAL_USE_MPFR
 #  endif // CGAL_USE_MPFR and no <mpfr.h>