diff --git a/src/rinterface_extra.c b/src/rinterface_extra.c
index 14d386742f3..b2bd0675950 100644
--- a/src/rinterface_extra.c
+++ b/src/rinterface_extra.c
@@ -3382,7 +3382,10 @@ igraph_error_t R_SEXP_to_vector_int_copy(SEXP sv, igraph_vector_int_t *v) {
   double *svv=REAL(sv);
   IGRAPH_CHECK(igraph_vector_int_init(v, n));
   for (igraph_integer_t i = 0; i<n; i++) {
-    VECTOR(*v)[i] = (igraph_integer_t)svv[i];
+    VECTOR(*v)[i] = (igraph_integer_t) svv[i];
+    if (VECTOR(*v)[i] != svv[i]) {
+      IGRAPH_ERRORF("The value %.17g is not representable as an integer.", IGRAPH_EINVAL, svv[i]);
+    }
   }
   return IGRAPH_SUCCESS;
 }