WASHINGTON • US Ambassador to Japan and the daughter of the late president John F. Kennedy, Ms Caroline Kennedy, has been criticised for using her private e-mail for official business.

These latest revelations about a high-ranking diplomat were given greater resonance in the light of the scandal hanging over former secretary of state Hillary Clinton.

A report by the State Department's Office of Inspector General (OIG) into the management of the Tokyo embassy has tagged Ms Kennedy with a similar charge to the one dogging the White House candidate.

The report released on Tuesday said that "senior embassy staff, including the Ambassador, used personal e-mail accounts to send and receive messages containing official business".

"In addition, OIG identified instances where e-mails labelled 'Sensitive but Unclassified' were sent from, or received by, personal e-mail accounts," it said.

US State Department guidelines require staff to use official e-mail accounts - judged more secure - to send government business, which then form part of the historical and legal record of their posts.

During her term leading the department between 2009 and 2013, Ms Clinton departed from this protocol, and used a personal server and private account for all e-mail. She has since handed over around half of the e-mails from the server to the department, so that they could judge whether they should be classified or made public.

But she has come under intense criticism for potentially exposing official business to hackers, and allegations that the 30,000 or so e-mails that she reportedly had wiped from the server could contain compromising material.

Ms Kennedy, a political appointee of President Barack Obama and not a career diplomat, will not face the same level of scrutiny as Ms Clinton, but the breach is further embarrassment for the US State Department.

AGENCE FRANCE-PRESSE