ISIS fighters in Syria (illustration)
ISIS fighters in Syria (illustration)Reuters

Senior security sources have estimated that an Islamic State (ISIS) attack inside Israel is merely a matter of time, as the number of Arab citizens of the Jewish state who support the terrorist group grows.

Just last week a surprise IDF general staff drill was held, in which the forces trained to deal with a mock large scale ISIS attack in the south, and a paratrooper brigade was scrambled.

The senior sources were cited by Yedioth Aharonoth on Monday estimating that as pressure builds on ISIS in Syria from Russian and US-coalition airstrikes, the group will increase its attacks outside of the war-torn state. Backing up the estimation the sources pointed to recent international attacks, including the Russian airliner downed in Sinai, the Paris attacks, and the California shooting last week.

Illustrating the threat, ISIS recently has started publishing its first videos in Hebrew threatening Israel with attacks, in which it vowed that "not a single Jew will be left in the country."

According to the sources, while the IDF knows where to hit other terror groups like Hezbollah and Hamas in response to attacks, there are no real targets to respond to against potential ISIS attacks, whether from Sinai or Syria on the Golan Heights.

"Who will we strike in Syria that the international coalition or the Russians aren't striking now?" posed the source.

Arab citizens of Israel have been growing more and more supportive of the brutal jihadist group as well; in 2014 there were eight cases of Arab Israelis involved in ISIS, but in 2015 that figure jumped to 14 cases, with a total of 34 suspects arrested. That number is still relatively low however compared to the numbers of Muslim ISIS recruits from European and other western states.

But the extent of support for ISIS is still worrying. A recent poll last month found that no less than 18.2% of Arab Muslim citizens of Israel, said they do not consider ISIS to be a radical terrorist organization, and that they are not ashamed of the brutal jihadist group. That number rose to 28.1% among supporters of the extremist Islamic Movement in Israel group specifically.

Israel Security Agency (ISA) assessments posit that there are several hundred Arab Israelis who actively support ISIS, although the poll would indicate that figure is somewhat underestimated. The Shin Bet says 32 Arab citizens have gone to Syria or Iraq to fight for ISIS, and seven of them were killed in Syria.

Just last weekend ISIS's Sinai commander Shadi al-Menei held a secret visit in Gaza for covert talks with Hamas. The two groups have kept their ties under wraps, as ISIS smuggles weapons into Gaza while Hamas provides it with advanced weaponry.