problem with non-latin characters in URL

valid_url will always return a FALSE for

http://news.google.com/news?pz=1&hl=ar&q=دروبال&cf=all&output=rss (this works in a browser)

where what is between &q= and &cf is the arabic word for drupal. Of course, if دروبال were replaced by its hex equivalent as in

http://news.google.com/news?pz=1&hl=ar&q=%D8%AF%D8%B1%D9%88%D8%A8%D8%A7%...

then valid_url return true.

Both should return TRUE and the user should not have to put hex.