Iphone keeps restarting

My phone will have the spinning wheel on a black screen, momentarily show the unlock screen and has the line that says something "iphone must be unlocked to complete update". I was unable to unlock it quick a couple of times but no luck in getting any of the information off of it. I have tried holding down the lock and home buttons to reset and it will continue to do the same thing. Unfortunately the phone is not backed up. I have lots of pictures and things I would like off of it. Any help would be appreciated.