diff --git a/core/plug-in/session_timer/SessionTimer.cpp b/core/plug-in/session_timer/SessionTimer.cpp
index 2bfa8a1c..6eae4d2c 100644
--- a/core/plug-in/session_timer/SessionTimer.cpp
+++ b/core/plug-in/session_timer/SessionTimer.cpp
@@ -269,6 +269,15 @@ void SessionTimer::updateTimer(AmSession* s, const AmSipRequest& req) {
     remote_timer_aware = key_in_list(getHeader(req.hdrs, SIP_HDR_SUPPORTED, SIP_HDR_SUPPORTED_COMPACT),
                                       TIMER_OPTION_TAG);
 
+    /* disable timers for this leg if not declare explicitly (UPDATE only) */
+    if (req.method == SIP_METH_UPDATE && !remote_timer_aware) {
+      /* timer is not supported by originator's leg */
+      DBG("Session timer not supported by request originator's leg, remove session timer intervals");
+      session_timer_conf.setEnableSessionTimer(false);
+      removeTimers(s);
+      return;
+    }
+
     // determine session interval
     string sess_expires_hdr = getHeader(req.hdrs,
                                         SIP_HDR_SESSION_EXPIRES,
@@ -361,8 +370,8 @@ void SessionTimer::updateTimer(AmSession* s, const AmSipReply& reply)
                                     TIMER_OPTION_TAG);
 
   if (!remote_timer_aware) {
-    /* timer NOT supported by B leg */
-    DBG("Session Timer NOT supported by leg B, removing internal session timer intervals");
+    /* timer is not supported by responder's leg */
+    DBG("Session timer not supported by responder's leg, remove session timer intervals");
     session_timer_conf.setEnableSessionTimer(false);
     removeTimers(s);
     return;