Berlin attack: Isis warned of festive season action

Islamic State warned a month ago that it would carry out sickening attacks during the holiday season in an eerie foreshadowing of the horror in Berlin.

Tourists were alerted that the US State Department had "credible information" that IS, al-Qaeda and other Islamic terror groups were plotting atrocities across Europe over the festive period.

The State Department informed citizens of a "heightened risk" of brutal massacres in crowded areas popular at Christmas time, advising tourists to "exercise caution at holiday festivals, events, and outdoor markets".

Now it appears the jihadists' dire warning has come true, after at least nine were killed when a large truck ploughed into a crowded Christmas market in the German capital. Early estimates suggest at least 50 people have been left injured following the attack, which police suspect may have been motivated by terror.

"Extremist sympathisers or self-radicalised extremists may conduct attacks during this period with little or no warning," the State Department said in a travel alert issued on November 21.

"Terrorists may employ a wide variety of tactics, using both conventional and non-conventional weapons and targeting both official and private interests."

In its warning, State Department noted the attacks in Belgium, France, Germany, and Turkey in the past year, saying it "remained concerned" over the potential for more.

It advised "vigilance when attending large holiday events, visiting tourist sites, using public transportation, and frequenting places of worship, restaurants, hotels, etc."

Tourists were told to "avoid large crowds, when possible", stay in touch with family and have an "emergency plan of action" ready.

But extreme caution does not typically tally with enjoying the festive spirit and making the most of the holidays. The chaos at Kaiser Wilhelm Memorial Church in Breitscheidplatz, a major public square in Berlin, happened at speed.

Facebook has now activated its safety check feature so friends and family can tell their loved ones they are unharmed.