You can try getting a really small jeweler's screwdriver (like people use on eyeglasses), and carefully work it in between on one side. Work slowly and carefully, if you can get it in far enough you should be able to break the seal and gently pry them apart. Do not use much force at all!
Edited: typing slow this morning, no coffee yet. Didn't mean to echo moulderhere's suggestion. But so far, two votes for jeweler's screwdriver.