Apple Inc.'s iCloud service may have been used to illegally access nude photos of actress Jennifer Lawrence and other celebrities, raising security concerns as the company prepares to unveil its newest iPhone.

Hackers posted the nude photos on the anonymous image-sharing website 4chan, the Telegraph in London reported. The photos targeting more than 100 celebrities were allegedly obtained by breaking into iCloud accounts, the newspaper said.

"This is a flagrant violation of privacy," the Telegraph quoted a spokesman for Oscar winner Lawrence as saying after confirming the photos. "The authorities have been contacted and will prosecute anyone who posts the stolen photos."