diff --git a/mercurial/hook.py b/mercurial/hook.py
--- a/mercurial/hook.py
+++ b/mercurial/hook.py
@@ -107,7 +107,7 @@ def _exthook(ui, repo, name, cmd, args, 
     if 'HG_URL' in env and env['HG_URL'].startswith('remote:http'):
         r = util.system(cmd, environ=env, cwd=cwd, out=ui)
     else:
-        r = util.system(cmd, environ=env, cwd=cwd)
+        r = util.system(cmd, environ=env, cwd=cwd, out=ui.fout)
     if r:
         desc, r = util.explainexit(r)
         if throw: