diff --git a/library/pk.c b/library/pk.c
index c29318dd97..e33a2434b9 100644
--- a/library/pk.c
+++ b/library/pk.c
@@ -968,6 +968,7 @@ static int copy_from_psa(mbedtls_svc_key_id_t key_id,
     } else
 #endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
     {
+        (void) key_bits;
         return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
     }