US authorities have warned troops to avoid drawing attention to their military ties on their social media accounts, ABC news reports.
The FBI and the Department of Homeland Security want current and former military members to check accounts for information that might attract the attention of the Islamic State group and its supporters, a bulletin to law enforcement agencies said.
The bulletin added that the Federal Bureau of Investigation had information indicating that people overseas were "spotting and assessing" people who were willing to commit attacks against current and former US-based military personnel.
Authorities are especially worried about the possibility of copycats inspired by two separate attacks on soldiers in Canada in October.
The first successful jihadist attacks on Canadian soil resulted in the deaths of two soldiers. Police said the two suspects in the separate incidents held jihadist sympathies and wished to join the IS group.
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Since the start of US-led air strikes against the IS group in Iraq and Syria, Washington has increased calls for vigilance.
In October, the State Department warned of the growing likelihood of retaliatory actions against American interests.
And in September, IS spokesman Abu Mohammed al-Adnani urged jihadist sympathizers living in coalition member countries to attack non-Muslim countrymen.
