The Federal Bureau of Investigation and Department of Homeland Security on Friday issued a warning to the local law enforcement authorities in the United States that Islamic State group supporters may target Christmas gatherings. Though there is no specific threat issued, pro-Islamic State group has published a list of churches across the US on its websites, reported Reuters.

In the bulletin, the FBI authorities have asked the police to watch out for suspicious activities. “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,” the FBI said in a statement.

FBI spokesperson Andrew Ames said citizens have also been asked to be aware of their surroundings and report suspicious activity. “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,” he told The Guardian.

Immediately after the warning was issued, President-elect Donald Trump raised the topic of the recent Berlin Christmas market attack and urged the world to combat the Islamic State group. “The terrorist who killed so many people in Germany said just before crime, ‘by God’s will we will slaughter you pigs, I swear, we will slaughter you’. This is a purely religious threat, which turned into reality. Such hatred! When will the US and all countries fight back?” he tweeted.