diff --git a/src/docx/opc/oxml.py b/src/docx/opc/oxml.py
index 570dcf413..36700bc54 100644
--- a/src/docx/opc/oxml.py
+++ b/src/docx/opc/oxml.py
@@ -27,7 +27,8 @@
 # ===========================================================================
 
 
-def parse_xml(text: str) -> etree._Element:  # pyright: ignore[reportPrivateUsage]
+# pyright: ignore[reportPrivateUsage]
+def parse_xml(text: str) -> etree._Element:
     """`etree.fromstring()` replacement that uses oxml parser."""
     return etree.fromstring(text, oxml_parser)
 
@@ -170,6 +171,8 @@ def target_mode(self):
 
         Defaults to ``Internal``.
         """
+        if self.target_ref and self.target_ref.startswith("#"):
+            return RTM.EXTERNAL
         return self.get("TargetMode", RTM.INTERNAL)