The FBI said it was addressing allegations that online accounts of celebrities had been hacked, leading to the posting of their private and personal photographs.

Authorities did not say what actions they are taking to investigate who was responsible for posting the photos. Apple said they are also investigating whether their online photo-sharing service had been hacked in order to get the images.

Representatives of female celebrities, including Oscar-winner Jennifer Lawrence, contacted authorities after the photos were posted Sunday.

In a prepared statement, Lawrence's representative Liz Mahoney said, "This is a flagrant violation of privacy. The authorities have been contacted and will prosecute anyone who posts the stolen photos of Jennifer Lawrence."   

Kate Upton's attorney told TMZ, it was an "outrageous violation" of their client's privacy.

According to TMZ, other alleged victims, include Victoria Justice, Ariana Grande, Kirsten Dunst, Hope Solo, Krysten Ritter, Yvonne Strahovski and Teresa Palmer, whose private photos were also posted.

The FBI said it was aware of the allegations, but refused to disclose further details of its investigation.

"We take user privacy very seriously and are actively investigating this report," said Apple spokesperson Natalie Kerris. She said they are investigating whether any iCloud accounts had been tampered with.

Mary Elizabeth Winstead confirmed that her photos were also posted online. The actress used Twitter to criticize those who were looking at her photos, which were taken privately with her husband years ago. She thought those photos were deleted. She said, "Knowing those photos were deleted long ago, I can only imagine the creepy effort that went into this."

Some of the celebrities, including Ariana Grande and Victoria Justice, claimed that the photos of them posted online were fake.