The FBI is investigating whether the financial records and other personal information of leading political figures, including Vice President Biden and first lady Michelle Obama, may have been illicitly accessed and published online, according to Justice Department officials.

A Web site posted what appear to be credit reports, banking information, Social Security numbers and addresses for several officials, as well as a number of celebrities. In addition to Biden and Obama, the site purported to have obtained records of Attorney General Eric H. Holder Jr., former secretary of state Hillary Rodham Clinton and FBI Director Robert S. Mueller III.

The Web site used the Internet suffix .su, which suggested that it was based in Russia or a post-Soviet republic.

It was unclear how the documents, if confirmed as authentic, could have been obtained. A Justice Department official, speaking on the condition of anonymity because the investigation is ongoing, said the FBI is trying to determine whether it might be a case of identity theft, hacking or perhaps both.

The White House declined to comment.

Much of the posted material was drawn from credit reports from organizations such as TransUnion and Equifax.

Tim Klein, a spokesman for the credit reporting agency Equifax, said the company was investigating “fraudulent and unauthorized access” to four consumer credit reports and is working closely with law enforcement officials.

“Nothing is more important to us than data security, and we have stringent measures in place for protecting the data entrusted to us,” Equifax said in a statement. “We enable consumers to access their credit reports through a variety of channels, including, which is a free service. In order for a consumer to have access to their credit report through this channel, they must provide Personally Identifiable Information that should be known only to the individual.”

TransUnion did not respond to a request for comment.

To obtain free credit reports, consumers are typically required to answer about five to seven questions that detail information such as the applicant’s monthly mortgage payment, who holds their car loan or the last payment amount on a particular credit card. It is not known how that kind of information was obtained about those whose credit reports were posted.

The Web site that posted the purported records also disclosed what it claims were the records of celebrities including Kim Kardashian, Ashton Kutcher, Arnold Schwarzenegger, Beyonce and Jay-Z.

In what appears to be a separate incident, former secretary of state Colin L. Powell’s Facebook and personal e-mail accounts also were hacked this week.

An unidentified hacker asserted responsibility for the breach in an e-mail sent early Tuesday to dozens of Washington journalists. The e-mail contained 16 images showing screenshots of Powell’s digital correspondence. None of the e-mails between Powell and his acquaintances — dated from 2005 to 2012 — appeared to be particularly revealing.

The images bore the handwritten word “GUCCIFER,” the name used by the hacker who obtained e-mails from the accounts of at least six Bush family members last month.

Powell told The Washington Post that he was aware his account had been breached. “I can confirm that the hacker was able to get into my old e-mails, and I’m taking precautions,” Powell said.

The day before, Powell’s Facebook page was hacked, with an unidentified person posting incendiary messages.

Powell later posted a message on his Facebook wall apologizing for the incident. “I’m sorry you have to see all the stupid, obscene posts that are popping up. Please ignore as we are working with fb to take care of this problem. I appreciate your patience,” he wrote.

Sari Horwitz, Julie Tate and Karen DeYoung contributed to this report.