Terrorist organization ISIS has recently released an eBook on how to 'migrate' to their so-called state, without being detected by Turkish security forces, in response to increased security measures taken by Turkey to prevent the crossing of foreign fighters to join ISIS in Syria.

According to reports, in the past 16 months, Turkish police have detained and deported a total of 560 foreigners in Istanbul alone, which have led terrorists to look for alternative ways to cross the border without being caught by Turkish authorities.

The book called 'Hijrah to the Islamic State' suggests that potential terrorists should avoid long beards, religious gear and should buy return tickets. On the other hand, women are advised to take their face coverings off, and even wear makeup and temporary tattoos to avoid looking 'suspicious.'

In May 2014, counter terrorism unit of Istanbul Police have established 'interview rooms' in airports, and have interviewed over 2500 passengers suspected to have ties with terrorist organizations.

40 police teams, who were dispatched in airports and bus terminals have received special training in profiling, risk analysis, tracking and interrogation methods. It was reported that the police officers involved in these duties speak other languages such as English, French, German, and Arabic.

Twenty-three questions, prepared by experts, are asked during interviews. More than 550 passengers admitted their intentions to join ISIS and were then deported following these interviews.

Several suspects were monitored closely because they gave suspicious answers during the interviews and some of them were caught red-handed by intelligence units while crossing the Turkish-Syrian border illegally.

A ministry official reportedly claimed two weeks ago that 20,000 people have been banned from crossing the Syrian border in an effort to prevent foreign fighters from entering Syria through Turkey. In late June the official number for those deported by Turkish authorities was 1,350.

The Foreign Ministry announced on Sept. 9 that the number had reached 2,100. In addition, officials said that through risk analysis systems designed to spot potential foreign fighters at airports, more than 1,400 people have been banned from Turkey.