The entertainment news website TMZ, which first reported the celebrity hacking, said it would not reveal the name of the website that had made public the private data of Britney Spears, Donald Trump, Jay-Z, Beyonce, Kim Kardashian, Paris Hilton, Mel Gibson, Ashton Kutcher, Vice President Joe Biden, FBI Director Robert Mueller, former Secretary of State Hillary Clinton, U.S. Attorney General Eric Holder and Los Angeles Police Chief Charlie Beck.
The Los Angeles Times reported the website appeared to originate in Russia.
"We'll take steps to find out who did this, and if they're within the boundaries of the United States, we'll prosecute them," Beck said.
Besides Social Security numbers, the personal data disclosed included home addresses, mortgage amounts, credit card information, car loans and bank accounts, TMZ said.
Biden and Clinton had the least among of information revealed, TMZ said.
TMZ said the FBI was looking into the matter as well.