Federal authorities have warned local law enforcement authorities across the nation that Islamic State sympathisers are continuing to call for attacks on churches and other holiday gathering sites.
The warning was issued yesterday after a publicly available list of US churches was posted on a militants' social media site.
It also came just days after an attack at a Christmas market in Berlin. Islamic State militants claimed responsibility for Monday's attack in which a truck plowed into the holiday market, killing 12 people and injuring 56.
"As part of the continuous dialogue with our law enforcement partners, the FBI routinely shares information about potential threats to better enable law enforcement to protect the communities they serve," FBI spokesman Andrew Ames said, adding that citizens are advised to maintain awareness of their surroundings and report suspicious activity.
"The FBI is aware of the recent link published online that urges attacks against US churches. As with similar threats, the FBI is tracking this matter while we investigate its credibility," he said. "We continue to work closely with our federal, state and local law enforcement partners should there be any potential threat to public safety.