diff --git a/django/template/__init__.py b/django/template/__init__.py
index 5493e5b..2f47482 100644
--- a/django/template/__init__.py
+++ b/django/template/__init__.py
@@ -267,14 +267,14 @@ class Parser(object):
                 var_node = self.create_variable_node(filter_expression)
                 self.extend_nodelist(nodelist, var_node,token)
             elif token.token_type == TOKEN_BLOCK:
-                if token.contents in parse_until:
-                    # put token back on token list so calling code knows why it terminated
-                    self.prepend_token(token)
-                    return nodelist
                 try:
                     command = token.contents.split()[0]
                 except IndexError:
                     self.empty_block_tag(token)
+                if command in parse_until:
+                    # put token back on token list so calling code knows why it terminated
+                    self.prepend_token(token)
+                    return nodelist
                 # execute callback function for this tag and append resulting node
                 self.enter_command(command, token)
                 try: