diff --git a/lib/less/parser.js b/lib/less/parser.js
index 8ca4e610..b03b046e 100644
--- a/lib/less/parser.js
+++ b/lib/less/parser.js
@@ -966,7 +966,7 @@ less.Parser = function Parser(env) {
 
                 if (value = $(this['import'])) {
                     return value;
-                } else if (name = $(/^@media|@page/) || $(/^@(?:-webkit-)?keyframes/)) {
+                } else if (name = $(/^@media|@page/) || $(/^@(?:-webkit-|-moz-)?keyframes/)) {
                     types = ($(/^[^{]+/) || '').trim();
                     if (rules = $(this.block)) {
                         return new(tree.Directive)(name + " " + types, rules);