This story has been updated.
Islamic State supporters have released what appears to be the personal information of former US government officials and enlisted US military personnel.
Twitter accounts tied to Islamic State (IS) published on Sunday the purported home addresses of ex-State Department and CIA officers as well as several dozen names and e-mails allegedly belonging to employees of the French Ministry of Defense. The information has not been verified by US officials.
Independent security analysts say releasing names and addresses of current and former officials suggests IS is ratcheting up its propaganda war by directly threatening high-profile figures.
"They're trying to stimulate interest in attacking senior officials, especially those interested in fighting ISIS," said Michael Smith II, chief operating officer of the defense consulting firm Kronos Security.
Mr. Smith said IS digital operatives have also rigorously advertised that they possess the addresses of even more current and former senior intelligence officials, including FBI Director James Comey and CIA Director John Brennan.
On Friday, IS supporters released names, e-mail addresses, and personal addresses of 160 members of the US Army and Marines and claimed to have obtained information on some 700 armed forces personnel.
The Pentagon would not comment on the lists but independent security experts said the information appears to be real even though it may not be the result of recent hacks into military computers.
"It is very likely that this is an authentic set of information," said Smith. "It does not benefit IS’s interest to publish false information."
The release of sensitive information about military personnel followed Anonymous's #TrollingDay campaign in which members and supporters of the online collective used Facebook, Twitter, and Instagram to attack IS affiliated accounts.
The #TrollingDay operations is also part of a wider Anonymous campaign to thwart the IS presence on the Web that started after the Charlie Hebdo shootings in Paris and picked up after November's coordinated terrorist attacks there that killed 130.
The Search for International Terrorist Entities Intelligence (SITE) Group, a private intelligence firm in Washington, first reported the appearance of lists of military personnel Friday afternoon. SITE attributed the release to the Cyber Caliphate Army, a hacking group with known IS ties.
"We can’t confirm that there was any hacking," said Rita Katz, director of SITE, even suggesting that some of the information could be fabricated. "It seems that the group is taking lists from military websites, collecting information from Google, and possibly even releasing bogus information."
Ms. Katz said the Cyber Caliphate has been involved in similar campaigns recently. On Twitter, the group has previously appeared as the "Islamic Cyber Army," staging campaigns dubbed #AmericaUnderHacks and #FranceUnderHacks that release personal details about military personnel, under the impression that it’s private information that's been stolen from military computes.
Katz says the group has not yet released any information that can’t be found through public sources such as Google searches.
Still, she said, "since some of the lists released by the pro-IS group are copied from US military sites, it's troubling that people affiliated with IS are seeing lists affiliated with the military, regardless of whether it is publicly available or not."
Hackers associated with IS have stolen sensitive US military information previously. In October, US prosecutors charged Ardit Ferizi, a citizen of Kosovo living in Malaysia, with stealing the personal information of more than 1,000 US military and federal employees and passing that data along to IS.