The FBI vowed to widen a probe into the massive hacking of naked celebrity photos if necessary, after new reported leaks including nude shots of Kim Kardashian.
The Federal Bureau of Investigation (FBI) launched an investigation earlier this month after a first batch of pictures, including of "Hunger Games" megastar Jennifer Lawrence, was published.
On Saturday US media reported that more nude celebrity photos, including reality star Kardashian and actress Vanessa Hudgens, had been circulating on social media.
The pictures, also including US soccer star Hope Solo, appeared briefly on 4chan and Reddit, before being removed, celebrity gossip site TMZ reported.
BuzzFeed said that personal videos and photos belonging to actresses Aubrey Plaza, Mary-Kate Olsen, Hayden Panettiere and Leelee Sobieski were posted, in addition to previously unseen pictures of Lawrence.
"The FBI's investigation into alleged computer intrusion/theft is continuing," FBI Los Angeles spokeswoman Laura Eimiller told AFP Monday.
"I'm unable to comment on specifics with regard to alleged victims, but any individual who believes they are a victim of these violations is encouraged to report it, if not already engaged with law enforcement," she added.
Hackers first released a trove of nude starlets' photos on September 1, after snatching them from Apple's iCloud in what the tech giant has called a "targeted attack".
The company has denied its cloud storage system was breached, suggesting that the celebrities had their accounts hacked by using easy-to-guess passwords, or by giving up their personal data to cyber criminals posing as Apple, a technique known as "phishing".
In addition to Lawrence, celebrities whose pictures were allegedly stolen and posted online in early September included model Kate Upton, singer Avril Lavigne and actress Gabrielle Union.