The U.S. Marine Corps is urging vigilance after the Islamic State group posted on the Internet what it says are the names, addresses and photographs of 100 U.S. military personnel and encouraged its supporters in the United States to kill them.
"It is recommended that Marines and family members check their online/social footprint, ensuring privacy settings are adjusted to limit the amount of available personal information," Marine Corps Spokesman Lieutenant John Caldwell said.
The Pentagon said it is investigating and said it always encourages servicemen and women to take appropriate protection procedures.
A group calling itself the Islamic State Hacking Division said the details of the service members, who it claims were involved in U.S. airstrikes against the Islamic State group in Iraq and Syria, came from government servers and databases.
Defense officials said, however, that it does not appear that the militants hacked the information from U.S. government website and that most of it is publicly available.
Meanwhile, on Sunday, CIA Director John Brennan said the momentum of Islamic State militants inside Iraq and Syria has been "blunted," adding that they are not on the march as they were several months ago.
In an interview on Fox News Sunday, Brennan said U.S. and Iraqi troops trying to push back against Islamic State fighters are making progress.