Delete groups using SP Client object model

   I'm trying to delete groups and Sites from Sharepoint using COM

Ex: Listitem i = ........;     i.DeleteObject(); 

Now, in my code , I'm using this snippet:

foreach (Group grpsSP in collGroup)
            {

                if (grpsSP.Title.Equals((grup.PK_Site).ToString() + "-1"))
                {

                    grpsSP.
                    clientContext.ExecuteQuery();

                    clientContext.ExecuteQuery();
                }
            }

but on the grpsSP object I don't find any reference to a Delete() method. Has anyone any idea about witch classes should I invoke to get the delete method? thanks!