I cannot remember the proper name for these, but they are not nails. They are more like rivits and the washers on the other side keep them in place. You'll have to bend up the washers, or carefully cut them with a pair of side cutters, then remove the stems. When you place the side cutters on the washers, move them side to side while applying pressure. Once the are cut through you should be able to remove them with needle-nose pliers.
I'm sorry for calling them nails but I didn't know what else to call them, they had a flat head and were pointy at the end. as for prying them up do you recommend anything specific to pry them?
Like I said, Use a pair of side cutters to lift them enought to cut them.