diff --git a/mustache.js b/mustache.js
index 19c8417..be1d7e6 100644
--- a/mustache.js
+++ b/mustache.js
@@ -62,7 +62,7 @@ var Mustache = function() {
       }
 
       var that = this;
-      var regex = new RegExp(this.otag + "%([\\w_-]+) ?([\\w]+=[\\w]+)?" +
+      var regex = new RegExp(this.otag + "%([\\w-]+) ?([\\w]+=[\\w]+)?" +
             this.ctag);
       return template.replace(regex, function(match, pragma, options) {
         if(!that.pragmas_implemented[pragma]) {