In a surprise major shake-up at Apple, Scott Forstall, Senior Vice President of iOS Software, is leaving. Forstall, who has been at the company since 1997 and is one of a handful of top executives who have become the face of Apple, will be out by 2013.

Apple doesn't appear to have plans of replacing Forstall, and instead will increase the responsibilities of surrounding vice presidents. Craig Federighi, previously the head of Mac OS X, will now take on iOS development as well, while Eddie Cue, head of Internet Software and Services, will take over Maps and Siri.

The reasoning for Forstall's ouster is not yet clear, although there have been reports that he was difficult to work with and had begun challenging the leadership of CEO Tim Cook. Forstall, who led development of iOS from the conception of the iPhone and was instrumental in the creation and implementation of Siri last year, has already been removed from the leadership page of Apple's website but is said to be sticking around as an advisor for the time being.

We'll have more on this story as it develops.

[via AllThingsD]