I flew from from MXP-IST-ORD recently and was wondering about the enhanced security measures at IST that were different than any other airport that I have experienced. When we arrived from MXP, we had to go through full security, although we never left the secure part of the airport. (I think). We passed by the Turkish Airlines transfer desk before security , if that helps. then we were allowed to the international gates in IST. Then, we went to our gate which was 228. Before the gate, we had to go through many different passport checks and security. They had blocked off access to gates 228,229,230 and the passengers to those flights were the only ones that could go there. The flights that were departing from those gates were Miami, Houston, and Chicago (interesting all are USA). We were issued through 3 different desks where people checked our passports. Then we had to go through a security section where they used batons to scan our bodies and did pat downs. Finally we were allowed to go to our gate. Does anyone know why we went though the first security, when we were just transferring, and why we went through all those passport checks en route to access to the three gates that all had USA flights? Was the passport checks just because they were USA flights? It was good to see all the security measures considering the attack that had happened at IST. Thanks for any answers- just trying to find out why this was.