The Pentagon and armed services have reached out to the roughly 100 service members whose personal information was posted online by a group that encouraged violence against them, claiming affiliation with ISIS.
The service members are being advised to exercise caution and stay off social media or limit their activity. Defense Department officials say that for now the service members and their families are not receiving additional security.
The group, which referred to itself as the Islamic State Hacking Division, said in English in an online posting that it had hacked military servers, databases and emails to obtain the information.
But defense officials say that the information was obtained from individual social media sites, and that there is no evidence that the group hacked into any government or military website.
The FBI and Defense Department are trying to determine who is behind the posting.