diff --git a/action.c b/action.c
index f75a39de9cf..570dc793f04 100644
--- a/action.c
+++ b/action.c
@@ -443,6 +443,31 @@ int do_action(struct action* a, struct sip_msg* msg)
 
 	ret=E_BUG;
 	switch ((unsigned char)a->type){
+		case ASSERT_T:
+				if (enable_asserts) {
+					/* if null expr => ignore if? */
+					if ((a->elem[0].type==EXPR_ST)&&a->elem[0].u.data){
+						v=eval_expr((struct expr*)a->elem[0].u.data, msg, 0);
+
+						ret=1;  /*default is continue */
+
+						if (v<=0) {
+							ret=0;
+
+							LM_CRIT("ASSERTION FAILED - %s\n", a->elem[1].u.string);
+
+							if (abort_on_assert) {
+								abort();
+							} else {
+								set_err_info(OSER_EC_ASSERT, OSER_EL_CRITIC, "assertion failed");
+								set_err_reply(500, "server error");
+
+								run_error_route(msg,0);
+							}
+						}
+					}
+				}
+			break;
 		case DROP_T:
 				script_trace("core", "drop", msg, a->file, a->line) ;
 				action_flags |= ACT_FL_DROP;
diff --git a/cfg.lex b/cfg.lex
index 3f69baf37ba..c0739a3294c 100644
--- a/cfg.lex
+++ b/cfg.lex
@@ -134,6 +134,7 @@
 
 /* action keywords */
 FORWARD	forward
+ASSERT	"assert"
 DROP	"drop"
 EXIT	"exit"
 RETURN	"return"
@@ -280,6 +281,8 @@ SCRIPTVAR_START	"$"
 
 /* config vars. */
 DEBUG	debug
+ENABLE_ASSERTS	enable_asserts
+ABORT_ON_ASSERT	abort_on_assert
 FORK	fork
 LOGSTDERROR	log_stderror
 LOGFACILITY	log_facility
@@ -449,6 +452,7 @@ IMPORTFILE      "import_file"
 <INITIAL>{EAT_ABLE}	{ count(); }
 
 <INITIAL>{FORWARD}	{count(); yylval.strval=yytext; return FORWARD; }
+<INITIAL>{ASSERT}	{count(); yylval.strval=yytext; return ASSERT; }
 <INITIAL>{DROP}	{ count(); yylval.strval=yytext; return DROP; }
 <INITIAL>{EXIT}	{ count(); yylval.strval=yytext; return EXIT; }
 <INITIAL>{RETURN}	{ count(); yylval.strval=yytext; return RETURN; }
@@ -580,6 +584,8 @@ IMPORTFILE      "import_file"
 <INITIAL>{MYSELF}	{ count(); yylval.strval=yytext; return MYSELF; }
 
 <INITIAL>{DEBUG}	{ count(); yylval.strval=yytext; return DEBUG; }
+<INITIAL>{ENABLE_ASSERTS}	{ count(); yylval.strval=yytext; return ENABLE_ASSERTS; }
+<INITIAL>{ABORT_ON_ASSERT}	{ count(); yylval.strval=yytext; return ABORT_ON_ASSERT; }
 <INITIAL>{FORK}		{ count(); yylval.strval=yytext; return FORK; }
 <INITIAL>{LOGSTDERROR}	{ yylval.strval=yytext; return LOGSTDERROR; }
 <INITIAL>{LOGFACILITY}	{ yylval.strval=yytext; return LOGFACILITY; }
diff --git a/cfg.y b/cfg.y
index 3830b251f5b..ff22bbba5e9 100644
--- a/cfg.y
+++ b/cfg.y
@@ -221,6 +221,7 @@ extern char *finame;
 %token FORWARD
 %token SEND
 %token DROP
+%token ASSERT
 %token EXIT
 %token RETURN
 %token LOG_TOK
@@ -316,6 +317,8 @@ extern char *finame;
 
 /* config vars. */
 %token DEBUG
+%token ENABLE_ASSERTS
+%token ABORT_ON_ASSERT
 %token FORK
 %token LOGSTDERROR
 %token LOGFACILITY
@@ -658,6 +661,10 @@ assign_stm: DEBUG EQUAL snumber {
 					*debug=$3;
 			}
 		| DEBUG EQUAL error  { yyerror("number  expected"); }
+		| ENABLE_ASSERTS EQUAL NUMBER  { enable_asserts=$3; }
+		| ENABLE_ASSERTS EQUAL error  { yyerror("boolean value expected"); }
+		| ABORT_ON_ASSERT EQUAL NUMBER  { abort_on_assert=$3; }
+		| ABORT_ON_ASSERT EQUAL error  { yyerror("boolean value expected"); }
 		| FORK  EQUAL NUMBER { dont_fork= !dont_fork ? ! $3:1; }
 		| FORK  EQUAL error  { yyerror("boolean value expected"); }
 		| LOGSTDERROR EQUAL NUMBER { if (!config_check) log_stderr=$3; }
@@ -2530,6 +2537,7 @@ cmd:	 FORWARD LPAREN STRING RPAREN	{ mk_action2( $$, FORWARD_T,
 		| SEND error { $$=0; yyerror("missing '(' or ')' ?"); }
 		| SEND LPAREN error RPAREN { $$=0; yyerror("bad send"
 													"argument"); }
+		| ASSERT LPAREN exp COMMA STRING RPAREN	{mk_action2( $$, ASSERT_T, EXPR_ST, STRING_ST, $3, $5); }
 		| DROP LPAREN RPAREN	{mk_action2( $$, DROP_T,0, 0, 0, 0); }
 		| DROP					{mk_action2( $$, DROP_T,0, 0, 0, 0); }
 		| EXIT LPAREN RPAREN	{mk_action2( $$, EXIT_T,0, 0, 0, 0); }
diff --git a/errinfo.h b/errinfo.h
index 41d4ba85761..235e571ac8d 100644
--- a/errinfo.h
+++ b/errinfo.h
@@ -35,6 +35,7 @@
 #define OSER_EC_PARSER	1 /*!< parse error */
 #define OSER_EC_PMEMORY	2 /*!< private memory error */
 #define OSER_EC_SMEMORY	3 /*!< share memory error */
+#define OSER_EC_ASSERT	4 /*!< assertion error */
 
 #define OSER_EL_CRITIC	1
 #define OSER_EL_HIGH	2
diff --git a/globals.h b/globals.h
index 99a08e76b3d..184eb61943e 100644
--- a/globals.h
+++ b/globals.h
@@ -171,4 +171,7 @@ extern char *db_version_table;
 extern char *db_default_url;
 
 extern int disable_503_translation;
+
+extern int enable_asserts;
+extern int abort_on_assert;
 #endif
diff --git a/main.c b/main.c
index e2f70b614ac..c3b6bb4b6f4 100644
--- a/main.c
+++ b/main.c
@@ -218,6 +218,10 @@ int sig_flag = 0;              /* last signal received */
 
 int dont_fork = 0;
 int no_daemon_mode = 0;
+/* assertion statements in script. disabled by default */
+int enable_asserts = 0;
+/* abort process on failed assertion. disabled by default */
+int abort_on_assert = 0;
 /* start by logging to stderr */
 int log_stderr = 1;
 /* log facility (see syslog(3)) */
diff --git a/route_struct.c b/route_struct.c
index ab422da7b38..9359ea44002 100644
--- a/route_struct.c
+++ b/route_struct.c
@@ -414,6 +414,9 @@ void print_action(struct action* t)
 		case SEND_T:
 				LM_DBG("send(");
 				break;
+		case ASSERT_T:
+				LM_DBG("assert(");
+				break;
 		case DROP_T:
 				LM_DBG("drop(");
 				break;
diff --git a/route_struct.h b/route_struct.h
index bc6d282186b..a9006abdfe2 100644
--- a/route_struct.h
+++ b/route_struct.h
@@ -61,7 +61,7 @@ enum { METHOD_O=1, URI_O, FROM_URI_O, TO_URI_O, SRCIP_O, SRCPORT_O,
 	   DSTIP_O, DSTPORT_O, PROTO_O, AF_O, MSGLEN_O, DEFAULT_O, ACTION_O,
 	   EXPR_O, NUMBER_O, NUMBERV_O, STRINGV_O, RETCODE_O, SCRIPTVAR_O};
 
-enum { FORWARD_T=1, SEND_T, DROP_T, LOG_T, ERROR_T, ROUTE_T, EXEC_T,
+enum { FORWARD_T=1, SEND_T, ASSERT_T, DROP_T, LOG_T, ERROR_T, ROUTE_T, EXEC_T,
 		SET_HOST_T, SET_HOSTPORT_T, SET_USER_T, SET_USERPASS_T,
 		SET_PORT_T, SET_URI_T, IF_T, MODULE_T, SET_DEBUG_T,
 		SETFLAG_T, RESETFLAG_T, ISFLAGSET_T ,