diff --git a/Mesh_3/include/CGAL/Mesh_3/search_for_connected_components_in_labeled_image.h b/Mesh_3/include/CGAL/Mesh_3/search_for_connected_components_in_labeled_image.h
index eeeec3d0271..83ce092a77d 100644
--- a/Mesh_3/include/CGAL/Mesh_3/search_for_connected_components_in_labeled_image.h
+++ b/Mesh_3/include/CGAL/Mesh_3/search_for_connected_components_in_labeled_image.h
@@ -73,16 +73,16 @@ search_for_connected_components_in_labeled_image(const CGAL::Image_3& image,
       for(uint i=0; i<nx; i++)
       {
         using CGAL::IMAGEIO::static_evaluate;
-#ifdef __GNUC__
+#if defined(__GNUC__) && !defined(__clang__)
 #  pragma GCC diagnostic push
-#  pragma GCC diagnostic ignored "-Wunknown-warning-option"
+#  pragma GCC diagnostic ignored "-Wpragmas"
 #  pragma GCC diagnostic ignored "-Wbitwise-instead-of-logical"
 #endif
         if(visited[voxel_index] | second_pass[voxel_index]) {
           ++voxel_index;
           continue;
         }
-#ifdef __GNUC__
+#if defined(__GNUC__) && !defined(__clang__)
 #  pragma GCC diagnostic pop
 #endif
         const Label current_label =
diff --git a/STL_Extension/include/CGAL/Uncertain.h b/STL_Extension/include/CGAL/Uncertain.h
index edb9b3b2dca..2652dec3f2e 100644
--- a/STL_Extension/include/CGAL/Uncertain.h
+++ b/STL_Extension/include/CGAL/Uncertain.h
@@ -289,9 +289,9 @@ Uncertain<bool> operator!(Uncertain<bool> a)
   return Uncertain<bool>(!a.sup(), !a.inf());
 }
 
-#ifdef __GNUC__
+#if defined(__GNUC__) && !defined(__clang__)
 #  pragma GCC diagnostic push
-#  pragma GCC diagnostic ignored "-Wunknown-warning-option"
+#  pragma GCC diagnostic ignored "-Wpragmas"
 #  pragma GCC diagnostic ignored "-Wbitwise-instead-of-logical"
 #endif
 inline
@@ -329,7 +329,7 @@ Uncertain<bool> operator&(Uncertain<bool> a, bool b)
 {
   return Uncertain<bool>(a.inf() & b, a.sup() & b);
 }
-#ifdef __GNUC__
+#if defined(__GNUC__) && !defined(__clang__)
 #  pragma GCC diagnostic pop
 #endif