iOS 8, uploading multi files into AWS S3 Bucket, while app running in the backgroud

I am new to AWS S3, working on app that will have a large number of files ( probably hundreds of 1 mb files ). Because of the large size I want to be able to perform this upload while app is in background mode. I went through the AWS documentation for http://ift.tt/1xNuskg But this does not talk about whether its possible for it to run while app is in background. This app is kind of like a dropbox for photos.

Feedback is welcome.