diff --git a/pungi/wrappers/kojiwrapper.py b/pungi/wrappers/kojiwrapper.py
index d53da5d9..b1f2459d 100644
--- a/pungi/wrappers/kojiwrapper.py
+++ b/pungi/wrappers/kojiwrapper.py
@@ -291,16 +291,21 @@ class KojiWrapper(object):
                 universal_newlines=True,
             )
 
-        first_line = output.splitlines()[0]
-        match = re.search(r"^(\d+)$", first_line)
-        if not match:
+        # Look for first line that contains only a number. This is the ID of
+        # the new task. Usually this should be the first line, but there may be
+        # warnings before it.
+        for line in output.splitlines():
+            match = re.search(r"^(\d+)$", line)
+            if match:
+                task_id = int(match.groups()[0])
+                break
+
+        if not task_id:
             raise RuntimeError(
                 "Could not find task ID in output. Command '%s' returned '%s'."
                 % (" ".join(command), output)
             )
 
-        task_id = int(match.groups()[0])
-
         self.save_task_id(task_id)
 
         retcode, output = self._wait_for_task(task_id, logfile=log_file)
diff --git a/tests/test_koji_wrapper.py b/tests/test_koji_wrapper.py
index 2a7c2df9..4b943596 100644
--- a/tests/test_koji_wrapper.py
+++ b/tests/test_koji_wrapper.py
@@ -668,6 +668,30 @@ class RunrootKojiWrapperTest(KojiWrapperBaseTestCase):
             ],
         )
 
+    @mock.patch("pungi.wrappers.kojiwrapper.run")
+    def test_run_runroot_cmd_with_warnings_before_task_id(self, run):
+        cmd = ["koji", "runroot", "--task-id"]
+        run.return_value = (0, "DeprecatioNWarning: whatever\n1234\n")
+        output = "Output ..."
+        self.koji._wait_for_task = mock.Mock(return_value=(0, output))
+
+        result = self.koji.run_runroot_cmd(cmd)
+        self.assertDictEqual(result, {"retcode": 0, "output": output, "task_id": 1234})
+        self.assertEqual(
+            run.call_args_list,
+            [
+                mock.call(
+                    cmd,
+                    can_fail=True,
+                    env={"FOO": "BAR", "PYTHONUNBUFFERED": "1"},
+                    buffer_size=-1,
+                    logfile=None,
+                    show_cmd=True,
+                    universal_newlines=True,
+                )
+            ],
+        )
+
     @mock.patch("shutil.rmtree")
     @mock.patch("tempfile.mkdtemp")
     @mock.patch("pungi.wrappers.kojiwrapper.run")