In the United States, Federal agencies 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. <br/><br/>The warning was issued last night after a publicly available list of US churches was posted on a terrorists' social media site. It also came just days after an attack at a Christmas market in Berlin. Islamic State terorists claimed responsibility for Monday's attack in which a truck plowed into the holiday market, killing 12 people and injuring more that 50.<br/>