diff --git a/fapi_validation.module b/fapi_validation.module
index 43eba43..bf82a00 100644
--- a/fapi_validation.module
+++ b/fapi_validation.module
@@ -110,6 +110,13 @@ function fapi_validation_rules_execute(&$element, &$form_state) {
     $ret = call_user_func_array($data[$rule]['callback'], $params);
 
     if (!$ret) {
+      // If an error callback or message was not set from the form rule
+      // definition, check to see if a default error callback exists
+      // in the rule data provided by modules integrating with fapi_validation.
+      if (!$error_callback && !$error_message && $data[$rule]['error callback']) {
+        $error_callback = $data[$rule]['error callback'];
+      }
+
       if (!is_null($error_callback)) {
         $error_params = array(
           $rule, $params, $element, $form_state