The application, which appeared in Apple's App Store on Monday and cost 99 cents to download, allowed a user to violently shake an iPhone screen to make a baby stop crying.

After enough shakes, the hand-drawn baby displayed on the screen stopped wailing and a large red 'X' appeared over each eye.

'This application was deeply offensive and should not have been approved for distribution on the App Store,' Apple said in a statement.

'When we learned of this mistake, the app was removed immediately,' it said. 'We sincerely apologize for this mistake and thank our customers for bringing this to our attention.' Tens of thousands of applications for the iPhone have been created by independent developers, but Apple has strict control over which ones are featured in the App Store.

Apple's apology came one day after The Sarah Jane Brain Foundation, a New York-based group which seeks to prevent brain injuries from Shaken Baby Syndrome (SBS), strongly condemned the 'Baby Shaker' application, which was submitted by an outside developer called Sikalosoft.

'Apple Inc, which notoriously and routinely rejects new apps from developers with a 'rigorous' vetting process, nonetheless apparently allowed this horrible application to be sold through its store,' the Foundation said.

The appearance of the 'Baby Shaker' came as California-based Apple celebrated the billionth application download from the App Store.

'Thanks a billion,' Apple said on its website after a counter ticked off the billionth download. 'Over 1 billion downloads in just nine months.' -- AFP