FILE PHOTO: The logo of the Wikileaks website is pictured on a smartphone in this picture illustration taken in Tokyo November 29, 2010. REUTERS/Toru Hanai/File Photo

WASHINGTON (Reuters) - Federal prosecutors in Alexandria, Virginia, have expanded a long-running grand jury investigation into WikiLeaks to include the leak of Central Intelligence Agency documents to the website, a source familiar with the inquiry said.

The source, who is familiar with the investigation and requested anonymity to discuss sensitive information, said the probe is focused on who leaked descriptions and technical information on techniques and tools the CIA has used to eavesdrop on intelligence targets to the website.

U.S. agencies have made only vague public comments on the latest WikiLeaks disclosures, but security and law enforcement officials familiar with the investigation said in the wake of the leaks that it is focused on whether an intelligence contractor was responsible. At this point, they said, investigators do not think Russia or another foreign government was involved.

U.S. officials have confirmed that Alexandria-based prosecutors have been conducting a federal grand jury investigation into WikiLeaks and its sources. Some court documents on elements of the inquiry have been made public.

The U.S. Justice Department declined to comment, as did a spokesman for the CIA, which has not publicly confirmed the authenticity of the material made public by WikiLeaks.

The website said the material it published comprised thousands of pages of internal CIA discussions about hacking techniques and the use of popular products such as Apple Inc iPhones; Google Inc Android devices; and Samsung Electronics television sets to spy on people.

WikiLeaks founder Julian Assange said his website would provide technology companies with access to the CIA hacking tools it acquired, enabling the companies to patch software vulnerabilities.