Petty Officer 3rd Class Kaylynn Barajas looks at photos of her children on Facebook while on a break in this November 2010 file photo. Officials have strongly urged those who serve in uniform to scrub their social media accounts of anything that might bring unwanted attention from 'violent extremists' or would help the extremists learn individual servicemembers’ identities.

The FBI on Sunday night issued the strongest warning yet about possible attacks by the Islamic State terrorist group against the U.S. military at home.

In a joint intelligence bulletin issued by the FBI with the Department of Homeland Security, first obtained by ABC News, officials strongly urged those who serve in uniform to scrub their social media accounts of anything that might bring unwanted attention from “violent extremists” or would help the extremists learn individual servicemembers’ identities.

“The FBI and DHS recommend that current and former members of the military review their online social media accounts for any information that might serve to attract the attention of ISIL [ISIS] and its supporters,” the federal bulletin sent to law enforcement agencies said, advising that troops “routinely exercise operational security in their interactions online.”

The Pentagon confirmed the bulletin was issued, but downplayed its significance.

“This is nothing new for us,” Defense Department spokesman Col. Steve Warren told reporters. “The department has long been aware and mindful of the potential for homegrown extremism, and we have continued to encourage and to advise all of our personnel to exercise the maximum amount of vigilance.”

Warren said DOD sent out a similar warning to troops in recent weeks after two uniformed Canadian soldiers were killed in Ottawa last month by self-proclaimed Islamic State supporters.

He said he is not aware of any new intelligence that might have compelled law enforcement agencies to issue the latest warning.

CNN noted that the FBI issued a security bulletin in October warning of similar attacks on U.S. soil against law enforcement personnel and members of the news media, and the U.S. Army in early October warned military personnel to be vigilant after Islamic State militants called on supporters to scour social media for addresses of their family members — and to “show up [at their homes] and slaughter them.”

The military bulletin advised against geolocating apps or posting home address information, and to limit those who can view personal information.

Officials told ABC News that they fear copycat attacks based on what happened in Canada last month.

news@stripes.com