EU counter-terror chief Gilles de Kerchove
EU counter-terror chief Gilles de KerchoveReuters

The European Union (EU) counter-terrorism chief on Tuesday revealed that since declaring itself an Islamic caliphate in June, the Islamic State (ISIS) terror group has seen a surge of European jihadists whose numbers jumped from 2,000 to 3,000.

EU counter-terror head Gilles de Kerchove told AFP that the boost in numbers comes following the declaration of Islamic statehood in the areas of Syria and Iraq conquered by the group, along with a highly intensive social media campaign to recruit western jihadists.

"My own assessment is that we're about 3,000," divulged de Kerchove, in estimating the number of Europeans fighting for ISIS in the Middle East. "The flow has not been dried up and therefore possibly the proclamation of the caliphate has had some impact."

Intelligence estimates have stated the number of ISIS fighters in Syria and Iraq stands at over 30,000, meaning that according to de Kerchove a full tenth of the Islamic State force is European.

The leading sources of ISIS foreign fighters are France, Britain, Germany, Belgium, The Netherlands, Sweden and Denmark. He added though that recently the group has seen an expanding grip in Spain, Italy, Ireland and Austria.

"Even a country like Austria I think has now foreign fighters, which I was not aware of before," said de Kerchove.

The growing threat in Italy has led to a recent increase in security at the Vatican, after appraisals reckoned "credible" threats that ISIS would try to assassinate Pope Francis.

In response to ISIS's ever-increasing sphere of influence, America has been gathering a coalition of western and Arab states, which has begun a campaign of airstrikes against the group in Iraq and now Syria.

Aside from the European nations, Australia has recently seen a spike in ISIS activity, with one cell recently arrested ahead of carrying out plans to behead a random member of the public, and a local terrorist shot dead after stabbing two police officers.

Israel has not been immune to the jihadist threat either, with an Arab citizen of Israel on Tuesday becoming the first Israeli convicted of returning from fighting for ISIS in Syria, in a severe threat to security. ISIS terrorists released a video showing how they took part in the recent Gaza terror war against Israel, and at least one former ISIS jihadist was killed in the Gaza fighting.

In response to the spreading reach of the jihadist organization threatening Israel, Arab citizens of Israel have shown ever-increasing support for ISIS, seen in such displays as flying ISIS flags and posting praise for the group on Facebook and other social media sites.