diff --git a/lib/less/parser.js b/lib/less/parser.js
index 2bc5c560..f50aaadd 100644
--- a/lib/less/parser.js
+++ b/lib/less/parser.js
@@ -1004,7 +1004,7 @@ less.Parser = function Parser(env) {
 
                 if (value = $(this['import'])) {
                     return value;
-                } else if (name = $(/^@media|@page/) || $(/^@(?:-webkit-|-moz-|-o-|-ms-)[a-z0-9-]+/) || $('keyframes')) {
+                } else if (name = $(/^@media|@page|@keyframes/) || $(/^@(?:-webkit-|-moz-|-o-|-ms-)[a-z0-9-]+/)) {
                     types = ($(/^[^{]+/) || '').trim();
                     if (rules = $(this.block)) {
                         return new(tree.Directive)(name + " " + types, rules);