Error during parsing of Atom response

I try to parse a HttpWebRequest from Yandex-Fotki (Image Hoster). I get a response in Atom-Format, but in SyndicationFeed I get an error: The element with name 'service' and namespace 'http://www.w3.org/2007/app' is not an allowed feed format.

My Code is:

XmlReader reader = XmlReader.Create(new StringReader(response));
            SyndicationFeed feed = SyndicationFeed.Load(reader);

Here is the input(response from the site):

<app:service xmlns:app="http://www.w3.org/2007/app" xmlns:atom="http://www.w3.org/2005/Atom">
  <app:workspace>
    <atom:title>packda на Яндекс.Фотках</atom:title>
    <app:collection href="http://api-fotki.yandex.ru/api/users/packda/albums/" id="album-list">
      <atom:title>Все альбомы пользователя packda</atom:title>
      <app:accept>application/atom+xml; type=entry, application/json; type=entry</app:accept>
    </app:collection>
    <app:collection href="http://api-fotki.yandex.ru/api/users/packda/photos/" id="photo-list">
      <atom:title>Все фотографии пользователя packda</atom:title>
      <app:accept>image/*</app:accept>
      <app:categories scheme="http://api-fotki.yandex.ru/api/users/packda/tags/" />
    </app:collection>
    <app:collection href="http://api-fotki.yandex.ru/api/users/packda/tags/" id="tag-list">
      <atom:title>Все теги пользователя packda</atom:title>
      <app:accept />
    </app:collection>
  </app:workspace>
</app:service>

I hope you can help me!