Pop star Madonna has urged fans not to distribute her nude images, which have leaked online.

The Material Girl hitmaker is furious after a number of unreleased images from old photoshoots hit the web and she has expressed her outrage by ranting about the alleged theft in a series of posts on photo-sharing site Instagram, reports contactmusic.com.

Madonna blames hackers for the leak and has asked fans not to buy or re-post the images, many of which she has uploaded to the social networking website as examples.

In a caption she writes: "Out takes from Steven Klein shoot I've never seen before. Thanks for showing me again and again that stealing selling and buying is alive and well in cyberspace!..."

She adds in another caption, "Another unreleased photo from a series I have just discovered! Stolen and sold to (sic) whom?? Wtf (what the f**k)? Are my fans doing this? If so I'm very confused! Stealing is a crime. #karma.""

The star went on to upload another picture and pleaded for the culprit to be found, adding: "This is a fitting photo I did not release (sic). I do not make money from the release of any of my photos. But other people do!

`I am asking my true fans and supporters who respect me as an artist and a human to not get involved with the purchasing trading or posting of unreleased images or music. I hope and pray we find the source of the leaks soon.

`Until then I am grateful for any leads or info and even more grateful for your support and loyalty! Please let me finish my work so I can give you my very best! Respect art and the process."

The incident follows the leak of the star's new track, `Rebel Heart`, earlier this month.