Execute backup via API

I am trying to use the API to execute backups. For openVZ it is all clear as vzdump is available via the API, but is there a similar option for KVM? It seems that from the web interface I can do the backup, but the API section doesn't seem to have that option (I am looking here: http://pve.proxmox.com/pve2-api-doc/).

If there is such an option, could you please point me to the API description for it.