diff --git a/phpseclib/Net/SSH2.php b/phpseclib/Net/SSH2.php
index 2a4ebe45..b47cfe5c 100644
--- a/phpseclib/Net/SSH2.php
+++ b/phpseclib/Net/SSH2.php
@@ -3533,7 +3533,11 @@ class Net_SSH2
 
         if (!is_resource($this->fsock) || feof($this->fsock)) {
             $this->bitmap = 0;
-            user_error('Connection closed (by server) prematurely ' . $elapsed . 's');
+            $str = 'Connection closed (by server) prematurely';
+            if (isset($elapsed)) {
+                $str.= ' ' . $elapsed . 's';
+            }
+            user_error($str);
             return false;
         }