We've been very clear I think from even before the administration started that their two girls would have a very private life, and we want to protect that private life and their privacy, White House press secretary Robert Gibbs said this morning when asked about the PCRM posters. And we hope that others will be respectful, as many in the media have been, about not using the girls as a publicity stunt.

The US White House has released a photograph of President Barack Obama's daughter Sasha sneaking up on her father as he works in the Oval Office.

The image has drawn comparisons with the famous 1963 image of John F Kennedy Jnr playing underneath the Oval Office desk as his father reads documents.