diff --git a/compiler/options.pas b/compiler/options.pas
index 2a7a8dff5f..3109045269 100644
--- a/compiler/options.pas
+++ b/compiler/options.pas
@@ -4004,8 +4004,10 @@ begin
       Message(option_w_unsupported_debug_format);
 
   { switch assembler if it's binary and we got -a on the cmdline }
-  if (cs_asm_leave in init_settings.globalswitches) and
-     (af_outputbinary in target_asm.flags) then
+  if ((cs_asm_leave in init_settings.globalswitches) and
+     (af_outputbinary in target_asm.flags)) or
+     { if -s is passed, we shouldn't call the internal assembler }
+     (cs_asm_extern in init_settings.globalswitches) then
    begin
      Message(option_switch_bin_to_src_assembler);
      set_target_asm(target_info.assemextern);